Beer from Stainless:
Producing Traditional British Cask Beers in America

Republished from BrewingTechniques' November/December 1993.

Although equipment limitations and cultural differences make exact replication of traditional British cask-conditioning practices all but impossible in the United States, attention to detail and a commitment to quality puts top-flight cask beers within the reach of American brewers. Pike Place brewers tell the story of their quest for the gentle pint.

Producing authentic versions of traditional beer styles poses a complex challenge to small American brewers. Equipment limitations, availability of appropriate raw materials, and lack of awareness on the parts of both publican and consumer present distinct challenges. After learning to deal realistically with the boundaries drawn by these three and spending time experimenting, we feel that we have achieved a successful balance. The following case study describes what we at Pike Place Brewery in Seattle have done to try to produce traditional British cask-conditioned ales.

BEGINNINGS

Practical challenges arose from the start, most of which involved product delivery systems and consumer expectations. In keeping with its traditional British objectives, for example, Pike Place Pale Ale was conditioned at first to a relatively low carbonation level of 1.9-2.0 volumes of carbon dioxide. We received complaints about "flat" beer, so we raised the level of carbonation to 2.5-2.6 volumes. At about this time a couple of local ale houses embarked on a plan of their own and began requesting cask-conditioned beers. We continued to produce brewery-conditioned beers at the higher level of carbonation but saw an opportunity in the budding market for cask beers. This is the story of how, over the following couple of years, we sought to satisfy this demand and at the same time realize our original objective of producing traditional ales.

RAW MATERIALS AND EVOLVING METHODS

Dry hops. Dry-hopping in the container is an excellent, traditional method of adding a pleasing, lively hop flavor and aroma. In the case of cask beer, where air is introduced as the beer is dispensed, the character constituent of the hops is completely different from that of a keg beer, where carbon dioxide keeps the hops and the beer in a more stable state. Air allows the contribution of the hops to soften along with other flavors in the beer. The rate of serving is also a factor. Traditional cask beers "live" for only a few days after they have been tapped and air admitted to the cask (see Table I). Higher gravity beers live longer. Different hop varieties function in specific ways when used for dry hopping (as they do for bittering and finishing), some performing quite well and others not so well. Generally speaking, good finishing hops work well for dry hopping, but close attention must be paid to the amounts used and the resultant character that the hops impart to the beer. We usually dry hop with English East Kent or British Columbia Goldings and find that larger amounts impart a tinny flavor to the beer over time. We therefore go easy, using as little as 1/6 oz. in a hop bag per 1/4 barrel of beer when we rack and prime.

Air. Enough cannot be said about the importance of air in the cask, both for its contribution to the dry hops and to the flavor of the customer's pint. In this technologically conscientious country, we have been taught that product stability and cleanliness are everything, especially in brewing. The fact remains, however, that just as air causes a robust wine to open up and become more accessible to the palate, air blends with cask beer to complete conditioning and to soften and generally bring forward flavors that otherwise might be indiscernible. Our cask ales are best about 24 h after they are tapped and air has become a part of the beer. It takes confidence to fly in the face of modern practice and allow one's hard-won beer to be influenced by oxygen, but the results can be truly wonderful.

Yeast. More than any other factor, the selection of yeast would prove to determine the character and behavior of a brewery's beers. It could be argued, in fact, that the performance characteristics of a brewery's yeast present the greatest challenges to the successful execution of cask-conditioned ales. Yeast must not only do its initial job of fermenting the beer well, but must also continue to function in the cask so that the finished beer can be properly attenuated and conditioned. It must settle, either on its own or by the addition of finings, so that the beer is stable, clean tasting, and bright. In short, it must perform well through all phases of its active life, and when its job is done get decently out of the way. A brewer must pay particularly close attention to the specific characteristics of the yeast when producing cask beers and not make unreasonable theoretical demands.

Pike Place yeast is extremely thermophyllic; it simply will not function except at relatively warm temperatures -- 66 degrees F (19 degrees C) or above -- which poses special problems in the production of cask beers. Not only must the temperature of our fermentation vessels be carefully monitored, but conditioning kegs, once primed, also must be kept warm. Other yeasts, less sensitive to drops in temperature (as when settled into cooler cellars, traditionally maintained at about 55 degrees F [13 degrees C]), would undoubtedly cause fewer problems, but by knowing our yeast we have come to recognize the necessity of being sensitive to its nature. Our yeast is also extremely flocculent and causes our beer to fall bright quite readily. The flocculation quality is good from the standpoint of clarity of the finished beer but can be problematic if the yeast has not remained in suspension long enough to complete the secondary fermentation required of true cask-conditioned beers. Again, by recognizing the yeast's characteristics, we found ways to work within its behavior parameters.

CONDITIONING

Next, we kegged early, four to five points (specific gravity) before terminal gravity. We reasoned that the beer could condition itself as fermentation concluded, but a surprising amount of yeast remained in suspension, and the resultant beer was cloudy, unstable, and inconsistent from test to test.

Eventually, we went back to priming, but this time by krŠusening with actively fermenting beer. We avoid having to ask our yeast to reawaken in the keg and still provide carbonation simply by the continued fermentation of the priming beer. We have found that for our beer 1 L of active fermenting beer per 1/4 bbl of flat, finished beer does the job quite nicely. The proper pitching rate for any beer is 1 X 106 cells/mL/ degrees P (that is, for 16 degrees P beer, pitch 16 X 106 cells/mL). The average doubling time is 4-8 h. Our pale ale at high kraeusen (12-18 h after pitching) has a specific gravity of approximately 1.040 ( approximately 10 degrees P), yielding approximately 5-10 X 107 cells/mL in the priming beer.

Fining. Because of the highly flocculent nature of our yeast and the necessarily rough treatment of beer in transport from the brewery to the serving establishment, our cask beers fare better without the use of finings. Because other yeasts could undoubtedly be helped along by finings, a few words must be said.

Traditional British practice is for beer to be fined in the cellar after delivery, but today -- and especially in this country -- it is necessary for the brewer to undertake such treatment. A number of products are available: gelatin, seaweed-derived tablets, isinglass, and other chemical clarifying agents. Most of our experiments used isinglass (we fine our regular keg beers -- all unfiltered -- with isinglass). We have settled on the use of Cryofine (A. Gusmer Incorporated, Cranford, New Jersey, USA). It is easy to mix and introduce, it is cost-effective, and the source company has been extremely helpful with our questions. We have also had good results with the seaweed-based Clarigene tablets (manufactured in the United Kingdom; available through various sources in the United States). In all cases, we added finings when priming and dry hopping.

With less-flocculent yeasts, finings carry the advantage of not only bonding with and causing yeast and haze particles to fall out, they also keep the settled material reasonably stable. With our cask beers, however, we noticed no improvement by their use and in fact found that our beer became cloudier and less stable.

It should be mentioned that finings have an odd tendency to stratify in the cask, and from time to time a thin layer may be encountered when pouring. Also, finings are also not heat stable and will fall apart if the temperature of the beer rises above 74 degrees F (23.5 degrees C).

CELLARING

At Pike Place, we keep our cask beer warm and stationary after priming and dry hopping. We monitor the level of carbonation and vent our kegs as necessary. Just before delivery, we draw off the sediment that has fallen in the natural course of conditioning. This method of tap venting, a subject of some debate in British circles (see the CAMRA publication Cellarmanship, in "Further Reading," below), provides a traditional yet practical solution to one of the problems posed by the limitations of American hardware. Best of all would be to package and maintain the beer in British containers using British methods, but availability of materials and practical issues of brewery management and beer distribution make such a level of dedication impractical (see "Stillage," below).

DISPENSING SYSTEMS AND KEG SELECTION

Some publicans choose to refrigerate tapped casks overnight and top them with carbon dioxide to prolong freshness. This practice has caused some debate in Britain, and a purist might frown on the introduction of any carbon dioxide to cask beer (as with a "cask breather"). Obvious problems with agitation arise when casks are moved, but if the bulk of the sediment is drawn off before moving the cask the practice can be manageable. Home brewers can easily modify 3- and 5-gal Cornelius kegs for cask beer by angling them topside-down, dispensing through the gas "in" tube, and admitting air through the long "out" tube. In all cases, experimentation will show the way to the elusive gentle pint.

Keg selection. Though they are suitable for the production of cask beer, American kegs have limitations. It is therefore desirable if at all possible to use traditional containers. British firkins, which contain approximately 10.5 U.S. gal (9 Imperial gal), are easy to transport and work with and are occasionally available for sale. Pike Place obtained its kegs from a Canadian brewery, which, incidentally, somewhat overestimated its market's commitment to cask ales. The other size most commonly used in Britain is the kilderkin, which is about twice the size of a firkin (approximately 21 U.S. gal).

One logistical problem is that British cask types and sizes are not universally approved for sale in all of the United States. Washington state law recently permitted the use of firkins, and we are hopeful that they will be more widely used in the future.

Traditional casks are manufactured with only a bung hole on the side and a keystone hole on one end. These holes are fitted with wooden plugs configured to allow the cask to be vented from the top and a tap fitted on the end. Once the cask has been placed and allowed to settle, a tool is driven into the soft center of the bung (see Figure 2), which is on top, allowing excess gas and usually some beer to escape. The hole is immediately fitted with a porous peg, or spile, which allows gas to continue to escape until the atmospheric pressure and the cask's internal pressure equilibrate. Once the cask has ceased releasing gas (usually a day or so after venting), a hard, nonporous spile is inserted, and the cask may be tapped.

Figure 2:
Tools used in cask cellaring and dispensing. Top: German wooden tap. Middle, left to right: wooden bung, keystone, venting tap (used during service in place of a hard spile because it has a valve that can be opened), hard spile. Bottom: British brass tap.

Taps are made of wood, plastic, brass, and stainless steel and are hammered through the keystone (Figure 2), providing a sealed fit. When tapping, care must be taken to prevent the keystone from cracking or breaking. If the keystone is damaged, the whole assembly may have to be replaced -- without agitating the beer. From this point on, whenever beer is poured, air must be admitted to replace the lost volume.

It is the responsibility of the server or cellarmaster to loosen or remove the peg as beer is dispensed to ensure that a steady stream is available and that the interior pressure remains reasonably constant -- sudden pressure changes (as when the flow slows to a trickle and the peg is suddenly loosened) can stir up finings and yeast sediment. Usually this involves simply removing the peg for the duration of service.

All this may be too much to ask of the busy publican. The Golden Gate keg offers a somewhat more manageable alternative -- the gas valve enables venting without the use of spiles. Nevertheless, there is much to be said for the balance between air, beer, and condition attainable by the slightest extra effort associated with traditional casks. Beer engines make it possible for the cask not to be disturbed in the course of its serving life, and mild refrigeration can provide ideal cellar temperatures (approximately 55 degrees F [13 degrees C]). Gravity service is somewhat trickier, because the ambient temperature of most taverns is well in excess of cellar temperature. Beer served too warm will go flat and "turn" more quickly. Excellent results can still be achieved by gravity feed, provided the beer is served rapidly enough.

The increasing use of beer engines, in fact, is one indication of a growing awareness of traditional serving methods and respectful treatment of hand-crafted beers. The home and craft brewing renaissance has placed many more choices within the grasp of the discerning consumer, and the responsibility of the publican has expanded well beyond the hook-it-up-and-pour philosophy so prevalent in post-war America. In addition to simply offering wide selections of locally made beers unheard of a dozen years ago, some publicans also offer their beers at different serving temperatures to make the best of widely varying styles and conditioning methods. Many have proven themselves willing to beat the bushes in the quest not only for new and interesting beers, but for serving equipment and, possibly most important, the knowledge derived from developing informed relationships with local brewers. More and more, consumers and publicans are expressing interest in cask beers.

Stillage. Stillage, or the spot in which the cask remains from the time of delivery until the time its contents have been emptied, is a seemingly small subject but one that requires mentioning. The desirability of the cask remaining stationary throughout its conditioning and serving dictates that space be designated, or some kind of rack or trestle constructed, in which it will be held, properly tipped and out of the way of other brewery or tavern activity. Our cask beers require 5-10 days' conditioning before it falls bright and the sediment is drawn off, during which time the casks remain undisturbed on a system of shelves. We built trestles that do double duty as serving stands for our traditional British containers (Figure 1).

Figure 1:
British firkin atop a handmade trestle. White decorative artwork over bright red background reflects traditional British style.