The Economics of Medieval English Brewing
Near the beginning of her autobiography, the fifteenth-century mystic Margery Kempe relates her ill-fated attempts to make her worldly fortune. Among her mercantile ventures, she turned her hand to brewing:
And than, for pure coveytyse & for to maynten hir pride, sche gan to brewyn & was on of þe grettest brewers in þe town N. a iij yer or iiij tyl sche lost mech good, for sche had neuyr vre þerto. For, thow sche had neuyr so good seruawntys & cunyng in brewyng, yet it wold neuyr preuyn wyth hem. For whan þe ale was as fayr standyng vndyr berm as any man mygth se, sodenly þe berm wold fallyn down þat alle þe ale was lost euery brewyng aftyr oþer, þat hir seruawntys weryn a-schamyd & wold not dwellyn wyth hir. Þan þis creatur þowt how God had punched hir be-for-tyme & sche cowd not be war, and now eftsons be lesyng of hir goodys, & þan sche left & brewyd no mor.
The basic narrative here seems clear enough. The town "N" is Margery's native town—Bishop's Lynn, as it was then known, although since the reign of Henry VIII it has been called King's Lynn. There Margery started a fairly large brewery, which failed for a technical reason: the barm, or yeast, fell, something we would now call a stuck fermentation. Her employees became embarrassed and quit. Perhaps they did not wish to be associated with someone against whom providential disfavor was so clearly directed, perhaps they merely thought her incompetent. The end result was that her business failed and she lost her capital.
For all its brevity, this account is a tantalizing glimpse into a craft which, considering its importance to daily life in medieval northern Europe, has attracted remarkably little systematic attention from scholars, and most of that attention has focused specifically on the role of alewives rather than the brewing industry as a whole. Despite the failure of her brewery, I would like to consider Margery Kempe as a typical commercial brewer at the beginning of the fifteenth century and place the hints she gives us into a wider context of how medieval English breweries functioned. I want to ask what it meant to be "one of the greatest brewers" in a fifteenth-century English town. How was her ale produced, sold and distributed? How did the consumption of ale affect the larger economy? What did being a brewer imply about her standing in the community? In answering these questions, we will find that Margery's adventure in brewing was notable only for its failure and because unlike her fellow brewers from the period she appears to us as a personality, not a mere name in a tax roll.
To understand how Margery's brewery would have operated, we need to put the surviving records into the context of the brewing process itself. These technical details are necessary first because the physical requirements of brewing in turn determine the economics of the trade; second, because while medieval and modern brewing are generally similar, there are enough important differences that we cannot assume a knowledge of modern beer translates to an understanding of the medieval equivalent; and third, because much of what has been written about the technical side of medieval brewing strikes me as inadequate. Judith Bennett, for example, has done admirable work on English alewives, but when she states that "English ale soured within only a few days," and that the ale trade was therefore entirely local, she over-simplifies to the point of being misleading. The factors affecting the spoilage of ale are complex, and there was a demonstrable non-local trade in ale in some places, including Margery's own town of Lynn.
The limited nature of the historical documents, of course, complicate any reconstruction of the economics of Margery's brew-house. For commercial brewers, the principal surviving records indicating their activities are the tax records for the assize of ale. While the assize by itself yields valuable data, it gives no indication about how profitable these brewers were, or what exactly went into their ale. Large noble and religious households, however, often did keep records related to their brewing, and since the physical process of brewing was essentially the same for private and commercial brewers alike, when these records are combined with data on market prices and taxation, a relatively complete picture of the ale trade emerges. In particular, I shall pay close attention to the granary accounts for St. Paul's Cathedral in London for the years 1283 and 1286. The salient data for 1286 are tabulated in the handout. To the best of my knowledge, the accounts themselves have never been given systematic analysis, and provide early, detailed evidence of the operation of an English brewery. They record not only the receipt and expenditure of grain but also the amount of ale produced and the various expenses for workers' salaries and equipment maintenance. Tellingly, the official in charge of these accounts was called the custos bracini, the warden of the brew-house, even though his responsibilities included the bakery, mill, and cellars as well as the brew-house.
All modern beers contain four basic ingredients: malted grain, primarily barley, hops, yeast, and water. In truly basic beer-making, however, the brewer needs only grain and hot water. Yeast, which ferments the beverage to make it alcoholic, occurs everywhere and will naturally settle onto this "grain tea" if it is left standing for any length of time, in much the same way it will naturally leaven bread-dough. Hops, which flavor and preserve the beer, are a comparatively recent introduction, and their mandatory use in all beers is, in fact, the major medieval innovation in brewing. Because of this simplicity, beer is among the oldest of known foodstuffs. The earliest instructions for making beer yet discovered were found on a 6000-year-old Sumerian tablet that describes a beverage made from a kind of barley bread, which was then steeped in water and allowed to ferment naturally. Such simple methods of producing beer, however, are not very efficient. Chemically speaking, the goal in brewing beer is to convert the starches found in raw grain into sugar, which the yeast can then consume, producing alcohol in the process. To convert more than a fraction of the starch to sugar requires an intricate, multi-step process, which was developed over a very long period of trial and error. Sumerian beer would have been high in unfermented starches, and low in alcohol. By the time we have any hints of medieval brewing procedures, a far more efficient system had been developed, evidently through many years of trial and error.
Necessarily, all beer and ale begins with raw grain. Early on, brewers discovered that barley was the best grain to use, although wheat, oats, rye, even rice, can be used as well. In those regions where all grains were available in sufficient quantities, barley's suitability for brewing was economically convenient. Barley alone is a poor bread-grain, since it lacks the gluten necessary to hold bread together. Wheat and other grains, by contrast, do not have as many of the enzymes necessary for brewing. By preference, therefore, barley was made into ale, and wheat into bread. This division is reflected in language. Barley was often used as a synecdoche for ale, and whenever a source refers simply to malt, or brasium in Latin, without identifying the type of grain, barley is implied. Margery would have had little difficulty in brewing entirely with barley. King's Lynn is in Norfolk, which was predominantly a barley growing region. Moreover, Lynn was a major center for the English grain market, and large quantities of grain were shipped through and stored in the town.
The effects of climate and soil upon crop yields, of course, frequently distorted this ideal. In many regions the demand for brewing grains greatly exceeded the available supplies of barley, and so brewers tended to use whatever grains were on hand. The costs of transport generally outweighed the benefits in improved quality. Wheat was in some places added to beer, but it was never the primary brewing grain. When writers refer to a wheat beer, they meant, as they still do today one that contained wheat, not one made entirely from it. Where the supply of barley was inadequate, brewers generally turned to oats. Exeter, in a region with a damp climate and sandy soils suitable primarily for oats, was well known for its oat beers into the 17th and 18th centuries. The area around London also produced large quantities of oats. Generally it has been assumed that these oats met the requirements of horse fodder for the city, but one hardly gets that impression from looking at the St. Paul's accounts.
The handout shows grain receipts and expenses for the year 1286. Each year, St. Paul's received a fixed quantity of grain and money from thirteen manors, in 45 separate deliveries. Depending on their sizes, different manors owed different numbers of payments, but the size of each payment was always the same: 3s. 10d. in cash, which went towards the servants' wages, 15 quarters of bread wheat, at seven bushels per quarter, 3 1/2 quarters of wheat ad grudum, literally "for the mash," to be used for ale, 3 1/2 quarters of barley, also for brewing, and 16 quarters of oats, measured at 8 quarters per bushel, the vast majority of which was again used for brewing. Each delivery was made on a different, precisely defined Sunday, which meant that regular brewing and baking consumed grain supplies at roughly the same rate they were brought in, obviating the need for the cathedral to store large quantities of grain. Notice that while oats make up 45% of all the grain supplied to St. Paul's, they only used 3% as horse fodder; 96% of the oats are used for brewing.
Clearly we cannot extrapolate the grain use of London from St. Paul's records. With their relatively sedentary lifestyle, canons must have had proportionately less need for horses, and hence horse fodder, than wealthy laymen. Our estimates are further complicated by the fact that once used in brewing, the grains, which still contained nutrients, were then reused to feed, if not horses, then at least pigs and other livestock. Nevertheless, other London brewers must have used a substantial portion of oats in their beer as well, and hence a significant proportion of the oats grown in the home counties must have gone, in its first use, to feed people rather than animals. Dr. Johnson would have been appalled.
Once the brewer has the raw grains, the first step in brewing is to malt them. From a description of malting in the mid-13th-century Treatise of Walter of Bibbesworth, we know that medieval malting was, except for the lack of mechanical processing equipment, essentially identical to modern techniques. First, the grains are soaked in water for several days, and then they are turned out onto the malt-house floor, where they begin to sprout. During this germination, the newly growing plant begins to break down the long starch molecules into shorter chains, and many of the necessary enzymes for the next step are developed. The sprouting grains are allowed to grow for several days, and dried to kill the acrospire. Drying was either done in the sun or in a kiln, each had its advantages. Sun-drying produced the cleanest tasting malt, but was, of course, dependent upon good weather, and the acrospire might continue to grow to the point where it consumed all the grain's nutrients, making it useless for brewing. Kiln drying, on the other hand, assured the growth was stopped at a precise moment and could be done in any weather, but the fuel used in the kiln imparted various flavors to the malt, many of which were considered undesirable. Straw and sea-coal were used where available as imparting the least taste, but most brewers used wood, and in some regions heather or peat, both of which left very strong aftertastes. Further, kiln drying could be difficult to control. Too great a heat would effectively toast the grain, destroying the necessary enzymes. A dark-brown color to the malt was an indication that it had been too severely heated to make good ale on its own, and was called "second-grade malt" (brasium commune or brasium cursale).
Malting is a discrete step in the brewing process, one that was very often done completely apart from the brewing. If kept dry, malt will keep for a year or more, so there's no particular requirement that malting be done close to the brewing day. Moreover, the requirement for a kiln made self-malting inconvenient for many small-scale brewers, and even larger brewers often preferred to receive their grain ready to brew. The result was that malt was frequently made on the farms, rather than at the brewery. Wellenborough manor in Oxfordshire malted roughly one third of all the grain they produced before sending that malt on to Crowland abbey for brewing. This specialization appears to have occurred at a very early date. The Domesday Book records malt as a frequent render.
References to money spent on repairs show that St. Paul's had its own kiln. Evidently, the canons did their own malting as well. One question not immediately evident from the accounts is how much of the grain was malted and how much was used raw. To compare with modern beers, when oats are used today, for example in Oatmeal Stout, they are used in much smaller percentages, rarely more than 10% of the total grain, and they are never malted. In theory, at least, some of this grain might have been used raw, particularly the wheat, which even today is considered difficult to malt. Frequent explicit references to oat malt, however, suggest that when oats were used in ale they were regularly malted, and indeed, the inventory of grain on hand at the time of St. Paul's 1283 accounting explicitly states that all of the grain currently in storage for the brew-house was malted: 17 1/2 quarters of malted wheat, 17 1/2 quarters of malted barley, and 70 quarters of malted oats.
Once the grain has been malted, the next step is to crush it to release the flour. It is worth remembering that this grinding requires a mill, which means unless brewers owned a hand quern, or in the case of large operations had their own mill, a fee, usually 1/24th of the grain milled, had to be paid to the local miller. It is possible to use the same mill for grinding, but the mash is more easily accomplished if the flour inside the grain is released without damaging the husks too severely, and thus one will find occasional reference to specialized malt-mills, which worked by pounding, rather than grinding, the grain. Saint Paul's had their own horse-mill, with two servants to operate it, which ground both bread flour and malt.
Once the malt has been crushed, hot water is added to the grain, a step called "mashing." During the mash, several enzymes within the grains work on the starches to break them down into sugars. Modern brewers know that these enzymes are active at different temperatures, and carefully manipulate the exact temperatures at which the mash sits to produce different effects in the final beer. Medieval brewers had no thermometers, of course, and only an imperfect understanding of the effects of various temperatures, which made the mash the most artful step in the process. The challenge was to add the just the right amount of scalding water to the cold malt. If the result was too cold, the enzymes would not become active, if too hot, they would be destroyed. If I had to suggest a cause other than divine interference for Margery's failure at brewing, I would guess it was her mash temperature. A mash at the wrong temperatures will yield a liquid high in unfermentable starches, and so the yeast will quickly use up the available food and then become dormant, producing exactly the symptom Margery describes.
After the grains have been mashed, the liquid, now sweet with sugars, is removed from the grain. In modern practice, this is done by sparging, which involves slowly drawing the liquid from the bottom of the mash vessel while additional hot water is sprinkled on the grains from above. The grain husks serve as a kind of giant sieve to filter out the undissolved particles from the liquid, which is known as wort. This process has the effect of washing all the sugar out of the grain. The older practice, described in later brewing guides and certainly used in the Middle Ages, was "parti-gyle" brewing, which involved drawing off the wort before adding more water to the grain, making a second, sometimes even a third infusion. Each infusion was naturally weaker than the previous one, and they could either be recombined, or used to make drinks of different strength. This latter practice gives rise to the term, familiar from Elizabethan and later literature, "small beer," made from the last and weakest infusion. The spent grain, which still had some nutritional value, was generally used, along with other byproducts from the brewing process, as animal feed. In 1283, St. Paul's brew-house earned £4 10s. 5d. from the sale of spent malt. Unfortunately, the accounts do not give the amount of spent malt actually sold or its unit value, so we cannot tell how much went to feed the house's own animals. If all of it was sold, however, the price was roughly 1d. per quarter.
The importance of small ale or beer in the overall consumption of ale and beer has probably been exaggerated. We know that when it was brewed, this drink was generally allocated to servants. But the assumption that this rather watery drink was the main beverage of ordinary people simply does not make sense. For that to be feasible, small beer would have to have been brewed in much greater quantities than the stronger first beer. But renaissance works on brewing make it clear that for a given quantity of beer made from the first runnings, only one third as much small beer could be made. In short, a large consumption of small beer implies an even greater quantity of strong beer. Much of the ordinary drink must have been "single" ale or beer, in other words a drink of moderate alcohol strength made directly from a moderate quantity of grain. I shall return to single ale and beer later. The St. Paul's accounts give a detailed record of how much ale each member of the cathedral household received, and make no mention of any differing strengths of beer. Apparently, no small ale was made, even though the large quantities of grain used would have permitted it.
One important ingredient of the preceding step is so obvious it is often overlooked: water. Brewers knew perfectly well that cleaner water meant better ale, and so sought the best supply. The demands major brewers placed upon a town's water supply, however, could be severe. The canons of St. Paul's brewed one hundred times in 1286, each batch yielding 678 gallons. Even more water than that, of course, had to be used. The grain itself absorbs a substantial amount of water during the mash, in this case about 260 gallons per batch, and we must also allow for water lost in the boil and in transferring the ale between vessels. All in all, at least 1000 gallons of water for one batch is a reasonable estimate. This one brewer, therefore, used over 100,000 gallons of fresh water every year. Moreover, they took this water not from the Thames, but from the conduit, for which right they paid an annual fee of 53s. 4d. Such demands, multiplied over a city full of brewers, eventually proved to outstrip capacity, for in 1345 London brewers were forbidden to take water from the conduit. Instead, they had to draw their water from the Thames, which eased the demands upon the city's water supply, but also greatly increased the amount of sediment in the brewing water.
Once the wort has been separated from the grains, it is boiled for a time with whatever flavorings are desired. Today, aside from a handful of specialty beers the only flavoring used in beer is hops, which are the leafy cones from a particular kind of vine. Hops provide a variety of different aromas and flavors to the beer, depending on their strain, but principally they make the beer bitter, which offsets the sweet taste of the raw wort, and they also contain antibacterial chemicals which help to preserve the beer. Hop shoots had been used as a food by the Romans, and for medicinal purposes throughout Europe, but they do not appear to have been used by the Celtic and Germanic tribes in making the "wine made from barley" that Tacitus and other historians of antiquity describe. The earliest reference to hopped beer comes from a 8th-century charter of the abbey of Saint-Denis, and spread through continental Europe during the course of the Middle Ages. England, however, clung to the unhopped beverage for an extraordinarily long time. It was not until the 15th century that hopped beer came to England, creating at the same time a distinction between the words ale and beer. In current usage, beer has become a generic term. Ale is style of beer, in contrast with lagers, and signifies a beer fermented at relatively warm temperatures with a different kind of yeast. That distinction, however, did not exist until the 19th century. The Old English word beor never seems to have been very common, and despite what the OED claims, was more likely used as a synonym for mead rather than ale. In any event, beer is rare in Middle English until the end of the fourteenth century, when it reappears, probably reborrowed from Dutch, to describe a hopped beverage imported from the continent. In his Dietary of 1542, Andrew Boorde explains the difference in a burst of national pride:
Ale is made of malte and water; and they the which do put any other thynge to ale than is rehersed, except yest, barme, or goddesgood [three synonyms], doth sophysticat there ale. Ale for an Englysshe man is a naturall drinke. Ale muste haue these properties, it muste be fresshe and cleare, it muste not be ropy, nor smoky, nor it must haue no wefte nor tayle. Ale shulde not be dronke vnder .v. dayes olde …. Barly malte maketh better ale than Oten malte or any other corne doth … Beere is made of malte, of hoppes, and water; it is a naturall drynke for a doche man, and nowe of late dayes it is moche vsed in Englande to the detryment of many Englysshe men … for the drynke is a colde drynke. Yet it doth make a man fatte, and doth inflate the bely, as it doth appere by the doche mennes faces and belyes.
The first English documents cited by the OED in which the term beer signifies the hopped beverage are customs records of the 1390's. One of them, interestingly enough, is for Margery Kempe's town of Lynn, where barrels of beer imported by alien merchants from the low countries were taxed. Margery herself records what must be among the earliest instances of hopped beer consumption in English literature. Recall that when she describes her brewery, Margery refers to the drink she produced as ale, using the ordinary word. Elsewhere in her narrative, she describes a scene where she is walking home from York on a hot summer's day with her husband: "beryng a botel wyth bere in hir hand." It is logical that Lynn, with its extensive mercantile ties to the Netherlands should be among the earliest places to which beer was imported, and that Margery, whose own family traded extensively in Germany and Flanders, should be an early English drinker of the beverage. Even more strikingly, she carries the beer in a bottle, although it's unclear whether this was the ordinary package for the drink (a surprisingly early instance, if so) or simply a convenient container for someone who needed to take her drink to go.
It was the preservative power of hops that eventually won them universal acceptance. Other spices could create an extraordinary variety of flavors in beer, but they lacked hops' preservative abilities, and so could only mask, rather than retard, spoilage. It was the suspicion that spices were a deceit, intended to hide the taste of bad ale, as much as simple conservatism which probably kept hops from being adopted for so long. When hopped beer was introduced, it was considered a separate beverage from ale, and was regulated separately. Originally, the London brewers guild made only ale, and there was a separate organization for beer-makers. Thus Tudor-era regulations prohibiting the use of hops in ale do not indicate, as is occasionally said, that hops were outlawed in England, but rather that laws were passed to maintain the distinction between ale and beer. The prohibitions did not last long. By the early seventeenth century most English were putting hops into their ale as well as their beer, albeit in smaller amounts. National prejudice eventually gave way to the practical realization that ale made with hops simply kept longer, regardless of its strength.
The next step is to boil the wort. With hops, the wort must be boiled at least an hour to dissolve the necessary chemicals. Without them, the boiling could in theory be skipped, which made the process of brewing simpler, and most importantly from the brewer's point of view, saved money on fuel. There are compelling reasons to boil the wort anyway. Sterilization of possibly contaminated water is one reason commonly cited, but to a certain extent "sterilization" is a misleading term. Wort is naturally acidic, and as a result pathogenic bacteria will not grow in it. Many other bacteria do grow quite well in ale and beer, but while they can make the drink taste so sour it becomes undrinkable, they will not do any serious harm. What will happen if the wort is not boiled is that bacteria already in the wort will multiply very rapidly, and have the potential to spoil the ale before it has finished fermenting. Boiling also has important effects on taste and appearance. In an oath taken by the contract brewers for Oxford University in 1449, the brewers promised "that they would boil their wort over a flame until it emitted a froth, and that they would skim the froth from the wort." The notion of a scum rising to the surface of the boiling wort may not sound very appetizing, but it does not indicate impure water or malt. Such a froth rises in modern brewing as well, and by removing it, the medieval brewers helped clarify their final product.
Once the boiling is complete, the wort must be cooled to the point where the yeast can begin to ferment. The wort was poured into wide shallow cooling troughs, and generally left overnight. Once cool, the wort was poured off the sediment that had settled in the bottom of the cooling troughs, yeast was beaten in, and the wort was poured into casks to ferment. Depending on the strength of the ale and the temperature in the cellar, it could take from a few days to over a week for the fermentation to complete. The ale was usually considered ready to serve within a day after fermentation had ceased. Medieval brewers had no idea exactly what yeast was, or even that it was a biological organism. The brewers knew quite well, however, that it was yeast which gave ale and beer their intoxicating quality. One of the synonyms Andrew Boorde uses for "yeast" in the passage I read earlier, godisgood nicely sums up brewers' feelings about this magical substance. It was imagined that yeast dissolved impurities in the wort; one eighteenth-century writer described it as "a very strong acid,". For this reason, what we now call fermentation was called "purification."
Practical experience had also shown medieval brewers that wort which was cooled quickly produced a better tasting and longer keeping drink. Rapid cooling followed by the introduction of a sufficient amount of active yeast minimizes the amount of bacteria that can form and reduces off tastes. When brewed in hot months, beer and ale were more liable to infection by undesirable bacteria. Brewers called such beer "foxed," because of the characteristic red tinge often seen on top of the fermenting yeast. Lacking a modern brewery's sterile procedures, brewers did their best by using the cooling tubs I have described, by brewing as much as possible in the cooler months, and by adding a large quantity of yeast to the wort rather than waiting for yeast to settle naturally. This last practice lead to a trade in yeast. Large brewers like the canons of St. Paul's, who had many batches fermenting throughout the year, had more than enough yeast to meat their needs. Small brewers, on the other hand, who might only have brewed a few times a year, tended to buy yeast from the larger brewers or from the bakers. In 1283, St. Paul's brew-house warden reported the rather substantial sum of 9£ 6s. 3/4d. received from sale of dregs, which contain all the yeast that falls out of suspension after the ale has finished fermenting.
From the process I've just described, the financial requirements for brewing become obvious. If a brewer buys malt ready made, the necessary equipment was not exceedingly expensive: a vat for heating water (most frequently made of lead), another for mashing the grain, wooden troughs for cooling, and barrels for fermenting. Such supplies would have been within the financial reach of all but the poorest households. To brew on any significant scale, however, obviously took substantially more capital, and studies of assize records have shown that most active brewers in a community tended to belong to the wealthiest families.
The economic basis for brewing in a large institution, where much of the ale produced was consumed internally was, of course, somewhat different from a commercial brewery. The combined brewery and bakery operation at St. Paul's turned a tidy profit for the canons: 25£ 19s. 1d. in 1286. Most of that money, however, came from the sale of surplus grain and byproducts of the operation: charcoal, spent malt, yeast, and so forth. Very little ale was actually sold, only 37 gallons that year, out of almost 68,000 gallons brewed. Production, in other words, was oriented towards internal consumption. The cathedral, however, had little need to sell its ale. Both grain and money to cover workers' wages were supplied as rent from the farms they owned.
Commercial brewers like Margery had additional burdens which the canons of St. Paul's could largely ignore. Not only did they have to purchase their grain on the open market, but they were subject to the assize of ale. As early as Anglo-Saxon England, some locales imposed a tax upon the selling of ale. Later, this system was supplanted by the assize.
Ostensibly, the assize controlled the profits that brewers could make on their product, penalizing them for selling their product at excessive prices. In fact, though, the values set were such that no commercial brewer could reasonably obey the assize, and it quickly grew to be a de facto tax on its own.
The assize for 51 Henry III, is representative: when a quarter of wheat sells for 3s or 3s 4d; a quarter of barley for 20d or 2s, and a quarter of oats for 16d., brewers in cities are to sell 2 gallons of ale for a penny, and those in the country, 3 or 4 gallons per penny.
Notice that the assize fixes the price of ale based on the price of the raw grains, and therefore implicitly fixes the maximum amount of malt that could be used without breaking the assize. The price in the country is as much as half that of the city, which reflects the added costs of transporting the grain. At the country price of 1/4 penny per gallon for a standard 36 gallon barrel will sell for 9d. To brew entirely from barley, we would need to make 3 barrels from one quarter simply to recover the cost of the grain. When we allow money for fuel, milling tolls, and a profit margin, we would need to make at least four barrels, perhaps even five. Our costs go up even further if we do not make our own malt, or take into account repairs to the brewery equipment or the wages of servants. Using less expensive oat malt will help, but not by much. Since renaissance recipes are unanimous that single beer is brewed at the ratio of 1 quarter of grain for 3 barrels, and since official ale-tasters ensured that brewers did not make their ale too watery, it is evident that it was virtually impossible to keep the assize, even if a brewer did not sell stronger varieties of beer. In other words, for practical purposes, the assize was a tax on commercial brewing.
Much of the trade in ale was driven by considerations of transport and spoilage. The common wisdom holds that because ale without hops spoiled so rapidly, the trade was entirely local. To a certain extent, the common wisdom is true, particularly in reference to ale of ordinary strength. Hopped beer keeps substantially longer than unhopped ale of the same strength. Scholars have, however, tended to exaggerate how quickly ale spoiled, and hence to overlook evidence to the contrary. First, as ale spoils, it grows increasingly sour. But this sourness is not necessarily an entirely bad thing, at least in moderation. Besides preserving beer, hops add bitterness to offset the sweetness of the wort. Without hops, the sourness caused by bacteria can serve the same function. Further, alcohol itself acts as a preservative, and ale brewed with as much grain as the canons of St. Paul's used can easily approach the strength of wine. Such ales could keep for months at the very least, particularly if brewed in winter. These strong ales were in fact exported from King's Lynn in significant quantities. For the year 1322-3, the records for customs paid by alien merchants upon exported goods show many shipments of ale leaving the harbor. The trade is entirely a winter one. The first ship carrying ale leaves on December 16, the last on March 16. And while the records simply call the ale cervisia with no indication of its strength, the value assigned to the goods, on average 1 1/2d. per gallon, make it clear that this ale is much stronger than ale sold at the assize. Weaker ales were not profitable to transport not merely because they spoiled quickly, but because they were too low in value to justify the shipping costs.
The social context for ale consumption is well known, and I will not belabor the integral role ale played in the social life of the medieval English. The generous ale allowances for monks, and the seeming omnipresence of brewers and ale-houses have given the impression that beer was the primary drink of most medieval English people, preferred for reasons of health as much as its intoxicating qualities. Judith Bennett, for instance, claims that "ale was virtually the only liquid consumed by medieval peasants (water was, probably justly, considered to be unhealthy." However if we consider the implications that ale-drinking on such a scale has for crop production, universal consumption becomes an untenable proposition.
Let me illustrate the consequences for Domesday England by supposing an average daily consumption of one gallon of ale per person. If ale were really the only drink, a gallon would not be very much. Estimates for the Domesday population vary, but I will assume a relatively low count of 1.5 million people. If they drank nothing but small beer, brewed at one quarter of grain for every three barrels, that implies an annual allocation of nearly 6 million quarters, 48 million bushels, of grain to brewing. If crops yielded an average of ten bushels per acre, 4.8 million acres of arable land would have been required just to grow beer grains, which is two-thirds of the all the land in England that Lennard estimates was under cultivation at the time. These numbers, of course, are very rough, but they assume low population and high crop yields for the time. In other words, they postulate the best plausible situation for surplus grain to devote to brewing. Even with such conservative figures, however, universal ale consumption would have required most grain to go into beer production rather than serving as a primary foodstuff. For a society that did not produce extraordinary surpluses of food to start with, that seems an implausible situation. Grain, in the form of bread and grain-based porridges, made up the base of the diet for the vast majority of medieval English and beer brewing always had second priority. During times of poor harvest, as happened for example during the Great Famine of 1315-1322, communities might ban the use of certain grains for use in beer.
In the later Middle Ages, of course, improvements in agriculture led to higher crop yields, reflected in additional ale production. Norfolk harvest workers, for example, received larger and larger allowances of ale as the centuries progressed. Nevertheless, ale consumption, at least by the poor, must have been much more occasional than is often admitted; agricultural production simply could not sustain it. Well-to-do peasants probably, and monks and gentry certainly, had enough ale available to have lived in a continual drunken haze if they so wished. Overall consumption, however, must have been very much less.
With the context I have sketched, we can now consider how closely Margery Kempe fits the prototype of a medieval brewer. Socially, Margery fit the profile exactly. She came from a wealthy family, and so could afford the investment in equipment, grain, and wages necessary to begin. She also considered brewing a means to enhance both her social and financial standing. As a married woman, brewing was considered a natural, socially approved profession for her to chose. Indeed, so strong was the stereotype of medieval wives as brewers that Margery may have been drawn by that stereotype into a profession for which she had little actual training, for economically, she was obviously a failure, and it is very likely that she exaggerated when she claimed to have been one of King's Lynn's largest brewers. There are only two records of Margery's brewing activities in the assize of ale, for the years 5 Henry IV and 6 Henry 4 (Sept. 30, 1403 - Sept 29, 1405). The records are under the name of Margery's husband, John Kempe, the normal practice for married women, and show the first year she brewed 6 quarters per week, and the second year 2 quarters a week. The amount of grain used during the first year is a reasonably large quantity, and supports her claim to be a commercial brewer. Six quarters, however, puts her in the second rank of commercial brewers in King's Lynn. At the end of the 14th century, for example, one brewer was in the assize was using four times that amount: 24 quarters per week, and a number of other brewers are shown brewing 8 or more quarters per week. 2 quarters per week, on the other hand, is a decidedly small amount for a commercial brewer. Perhaps it reflects Margery's troubles with her yeast, but I cannot help but feel Margery's story is suspiciously tidy. Margery would have us believe she was one of the greatest brewer in Lynn for 3 or 4 years before her career was cut short by divine intervention, but for a fermentation to fail in the manner she describes implies incompetence in brewing, hardly likely if she had been brewing successfully for some years before the mishap. A more likely explanation, supported by the assize records, is that she never managed to brew very successfully, and that her later recounting of her time as an alewife shaped events to fit her desire to see her life as affected by divine providence.
 Margery Kempe, The Book of Margery Kempe, ed. Sanford Brown Meech. Early English Text Society, Original Series, no. 212, pp. 9-10.
 Judith M. Bennett, Women in the Medieval English Countryside: Gender & Household in Brigstock Before the Plague. Oxford UP (1987), p. 120.
 The Domesday of St. Paul's of the year M.CC.XXII., ed. William Hale Hale. Camden Society (1858)., pp. 154-75. These documents have attracted brief attention in some popular histories of brewing, but their accounts are garbled. The word Domesday seems to have mislead some authors into believing that the records appear in the Domesday Book and hence are eleventh, rather than thirteenth century. See, for example, Randy Modher, The Brewers Companion. Alephenalia (1992), p. 19.
 Many books give step-by-step accounts of the brewing process. See, for example, Byron Burch, Brewing Quality Beers, 2nd ed. Joby Books, 1993. Readers who want more detail on the chemical basis of the process should consult George Fix, Principles of Brewing Science. Brewers Publications, 1989.
 In the "Hymn to Ninkasi". To call this hymn a recipe is somewhat misleading. It gives a general description of making beer, but no specific measurements. Modern brewers, however, have attempted to reconstruct the process. A translation of the hymn is available online
 Maryanne Kowaleski, Local markets and regional trade in medieval Exeter. Cambridge UP (1995), p. 14.
 Bruce M. S. Campbell, "Ecology Versus Economics in Late Thirteenth- and Early Fourteenth-Century English Agriculture," in Agriculture in the Middle Ages, ed. Del Sweeney, U of Pennsylvania P (1995), p. 82.
 In his dictionary, Johnson defines oats this way: "A grain, which in England is generally given to horses, but in Scotland appears to support the people."
 Walter of Bibbesworth, Le Traité de Walter de Bibbesworth, ed. Annie Owen (1929).
 Frances M. Page, ed. Wellingborough Manorial Accounts, A.D. 1258-1323, from the Account Rolls of Crowland Abbey. Northamptonshire Record Society, 1936.
 Domesday Book. A Survey of the Counties of England. General ed., John Morris. 35 vols. See, for example vol 13, Buckinghamshire, 12,3; and vol. 25, Shropshire 4,4,11.
 Hale, p. 170.
 See, for example, Gervase Markham. The English Hus-Wife. London, 1616.
 The measure used in the original is a "bolla"; exactly how large this was is uncertain, but approximately one gallon is a reasonable estimate, given the quantities of grain used.
 Léo Moulin "Bière, houblon et cervoise," Bulletin de l'Académie Royale de la Langue et de la Litérature Françaises, Vol. 59 (1981), p. 122.
 Andrewe Boorde. A Compendyous Regymentor a Dyetary of helth. (1557), fol. G.ii - iii.
 Kempe, p. 23
 Neither the OED nor the MED cites this occurrence, although it is a strikingly early appearance.
 "quod aquam tamdiu conquerent super ignem quamdiu emitteret spumam, et quod mundarent spumam ab aqua" Munimenta Academica, or Documents Illustrative of Academical Life and Studies at Oxford. ed. Henry Anstley, 2 vols. Rolls Series, 50. London, 1868. (vol. 2, p. 541).
 William Ellis. The London and Country Brewer. 2nd ed. (1736), p. 76.
 Kowaleski's discussion of the situation in Exeter likely reflects the general situation in many medieval English communities. Cf. op. cit., pp. 129-132.
 The Domesday book records, for example, that there was a ten-pence tax in Hereford: "Cujusconque uxor braziabat intus et extra ciuitatem; dabat .x. denarios per consuetudinem." (192a)
 This analysis dovetails with Kowaleski's comment that "By the early fourteenth century...the annual amercements for breaking the assize of ale had become little more than a type of licensing fee for the privilege of brewing and retailing ale." Ibid., p. 187.
 One variety of modern beer, lambic, deliberately uses certain bacteria for just this sort of sourness. They do use hops, but generally of a mild variety.
 Dorothy M. Owen, The Making of King's Lynn. Records of Social and Economic History, n.s. 9. British Academy (1984), p. 343-6.
 Bennett, ibid.
 Estimates range from 1.1 to over 25 million. For a summary, see Richard Smith, "Human Resources," in The Countryside of Medieval England, ed. Grenville Astill and Annie Grant. Blackwell (1988), p. 190.
 R. Lennard, Rural England 1086-1135. Oxford UP (1959), p. 393. The estimate of 10 bushels per acre is a relatively generous one for the period; later recorded yields were often less (although in some regions they could be higher). Additionally, since some seed must be reserved for to sow the next season's crop, the actual amounts harvested would need to be at least 12 to 15 bushels per acre to afford this much grain for actual consumption. Summaries of documented crop yields and ratios from later periods are given in Christopher Dyer, Standards of Living in the Later Middle Ages: Social Change in England, c. 1200-1500. Cambridge UP (1989), pp. 127-131.
 Chrstopher Dyer, "English Diet in the Later Middle Ages," pp. 191-214 in Social Relations and Ideas: Essays in Honour of R.H. Hilton, T.H. Aston, P.R. Cross, C.C. Dyer and J. Thirsk, eds. London, 1983.
 See The Statutes of the Realm, vol. 1. London, 1810. AD 1315, 8&9 Edw II (I.340b) "Ad Petitionem eorundem, supplicantium Regi & ejus Consilio, quod Breve de Cancellaria eisdem Burgensibus ad proclamandum in dicta Villa Wynton' concedatur, Quod nulli Braciatores seu Braciatrices in eadum Villa Braseum de certo faciant de Frumento, quia Frumentum in illa Patria destructum est."
 Dyer, Standards of Living, p. 158.
 Kempe, p. 364.
 Owen, p. 421.