By Jim Busch (Brewing Techniques)
This article covers some of the concepts and techniques involved in brewing, conditioning, and serving cask-conditioned ales, also known as real ales. Although this article is oriented to home brewers’ methods, it touches on concepts that can be of benefit to professional craft brewers as well.
Cask-conditioned dispense of real ale is the traditional method of serving beer in the pubs of Britain. It dates back hundreds of years, long before pressurized tanks of carbon dioxide became the predominant method of dispense throughout the world. The hold-out traditionalists in Britain are best represented by members of Britain’s Campaign for Real Ale (CAMRA), a consumer organization that advocates adherence to uncompromising standards for the production and dispense of real ale. Britain also hosts plenty of intelligent brewers whose primary concern is the end product, tradition be damned (or at least moderated). The brewing community has enormous room for both schools of thought, and one should be careful not to disparage the other for their choices in these matters. The end result is in the pint, and both traditional and modern methods can produce astoundingly good pints of ale.
At its simplest, real ale is an unfiltered ale that has had a degree of conditioning in the cask and is dispensed from this same cask into the consumer’s glass. From this definition, most kegged homebrew qualifies as cask-conditioned. A better term for the common homebrewed variant, however, would be “keg conditioned”; traditional real ale must meet more stringent guidelines.
CAMRA defines real ale as beer made from traditional ingredients, matured by secondary fermentation in the container from which it is to be served, and dispensed without the use of extraneous carbon dioxide. More specifically, traditional real ale is marked by the following characteristics:
The brewing of real ale is not that different from what most home brewers already do: Use the freshest ingredients and serve the beer in a fresh state. Although these alone are huge factors in successfully making real ales, I can add a few more suggestions.
If possible, use British pale ale malt for a fuller tasting ale. Also, use British or Belgian caramel malts, or even German caramel malts for that matter; the fullness of the European and British caramel malts make a better real ale. When making British-style real ales, use British hops like Goldings, Fuggles, Challenger, or Target. The Slovenian Styrian Goldings are also excellent.
Real ales are usually much weaker in alcohol than the normal kegged ale from the United States: bitters are 3–3.8% (v/v), best bitters are 3.8–4.4% (v/v), and strong bitters are 4.5–6% (v/v). The low carbonation, snappy hoppiness, and lower alcohol levels of the bitters make for a fantastic session beer, one that can be drunk for many 20-oz pints in one sitting.
It also helps to use an authentic British ale yeast, and, if possible, open fermentation. The fruity character of a British yeast blends well in these beers. I’ve also had excellent results using American ale yeast and U.S. hop varieties like Cascade and Mt. Hood.
Cask-conditioned ales are often dry-hopped in the cask. I have had great success using a nylon hop bag. I tend to use between 0.5 and 1 oz of fresh whole hops per 5-gal Cornelius can. My favorite hops for this purpose are East Kent Goldings, Styrian Goldings, Fuggles, and Cascades. Dry hopping in the cask is a great way to experiment with different types and amounts of hops; it’s often quite easy to distinguish the character and aroma of a particular hop.
You can also avoid cask hopping and opt for dry hopping in the primary or secondary fermentor — or avoid cask and dry hopping altogether and serve a less aromatic beer.
The term finings encompasses the group of products that aid in the precipitation of proteins, tannins, and yeasts. Many kinds of finings exist, including isinglass, gelatin, and Polyclar, to name a few.
A word of caution on a few common fining agents. Polyclar, or PVPP, is a fining that aids the removal of polyphenols by precipitating phenols. It reduces chill haze, but can leave remaining yeast to cloud the beer. Cryofine is a form of processed isinglass that is quite easy to use because it requires little preparation other than blending with water or beer; no acid pH reduction is needed.
Unfortunately, the manufacturer specifically notes that it is intended for use in bulk tanks before filtration to reduce the yeast load on the filter. Compared with traditionally prepared isinglass, it is not nearly as effective in rapidly dropping yeast and proteins, nor is it as effective in resedimenting yeast that has been stirred up after the initial fining. It does work, but less effectively than other forms of isinglass.
Gelatins and isinglass have good success in cask ales. Isinglass is undoubtedly the most used fining for real ale, and its performance is astounding. It is composed of almost pure collagen, extracted from the swim bladder of certain fish (such as sturgeon). The accompanying box shows how to use it for a 5-gal batch of cask-conditioned homebrew.
The protein isinglass contains three chains of amino acids wound around each other, with a complex hydrogen bonding system holding them together. In beer, isinglass is close to its isoelectric point and carries a high charge density of both positive and negative charges along its structure. Because it exhibits both charges, it has the remarkable ability to attract both negatively and positively charged particles, including yeasts, proteins, and tannins. These particles coalesce and rapidly drop to the bottom of the vessel.
The clarity that can be achieved in a matter of days with 1 teaspoon of isinglass per 5 gallons of ale is quite impressive. As an added benefit it improves head retention, believed to be a result of its ability to react with foam-negative phospholipids that precipitate with the finings.
Real ales require between 2 and 10 days of conditioning time, depending on how young the beer is when it is casked, how strong the beer is, and how much priming sugar or kräusen beer was added at casking time. The conditioning period should result in the product being almost or fully fermented and should also allow time for the finings materials to precipitate proteins and yeast.
After this period, traditionalists vent their authentic British casks using a soft spile (a porous wooden peg — see photo at right). The soft spile allows slow, gentle venting of the carbon dioxide while preventing agitation of the trub. Those less committed to traditional methods vent the excess carbon dioxide directly out of the relief valve of their Cornelius soda can or Sankey-type keg. In either case, the goal is to end up with a semib-right to brilliant ale of low carbonation.
After venting to ambient pressure, traditionalists replace the soft spile with a hard spile (nonporous wooden peg) until the cask is tapped. Once the cask is tapped, the soft spile is removed so the keg can breathe and the real ale can flow out the tap; it is returned to the cask when the cask is not in service.
How to Use Dry Isinglass in the Home Brewery
The most popular fining agent among breweries serving conditioned ale from the cask, isinglass can help your real ale fall brilliantly clear. Here’s how to prepare and apply it in the home brewery.
Preparation: Add 1–2 tsp isinglass to 200 mL of boiled and cooled water, adjusted to a pH of 2–3 (I have used beer with good success also). Blend in a sanitized blender for 2 min. Allow to settle for 5–10 min, then blend again. Repeat several times. (It is helpful if the water or beer is chilled.)
Application: Add to cask, either at filling time along with priming solution or after the cask has conditioned. If the isinglass is added after the cask has conditioned, be prepared for foaming and therefore be ready to close the keg lid quickly. Once the isinglass is added, lay the cask on its side and roll it back and forth to mix the contents thoroughly. Stand the cask upright (or in its stillage) and allow to settle until dispensing.
Storage: If the prepared finings are not going to be used immediately, keep them cold. Finings work best between 40 and 60 °F (5 and 15 °C) and become almost useless above 68 °F (20 °C).
Home brewers can easily cut the bottom 0.5–1.5 in. off of the dip tube on the Cornelius keg liquid line. Sankey-type kegs require the stem to be removed and then shortened by at least 1 in. The reason for the shortened tubes is to allow room for the yeast, proteins, and finings to settle, thereby allowing dispense of relatively clear beer.
Cask-conditioned dispensing refers to the serving of ale without the use of extraneous carbon dioxide, which keeps it from becoming more carbonated than it has become by natural means.
The oldest and simplest method of dispense is to use gravity to dispense directly into the glass from the cask’s tap. To gravity-dispense from a Cornelius keg, carefully mount the keg on its side and pull the beer from a short spigot through what is normally the CO2-In line. The other fitting, which is normally the Beer-Out line, is vented to allow the beer to flow.
When gravity dispensing from Cornelius kegs, it is useful to arrange a stillage to position the cask in place for the duration of conditioning and dispense. Real ales that are moved the least during conditioning through to dispensing will be brightest, but some movement can be carefully controlled with success, particularly if you dispense using Cornelius kegs and an authentic beer engine.
A beer engine is a fancy hand-operated pump that literally pulls the beer from the cask, forcing it through a spigot into the waiting glass. This is the most common form of dispense in Britain, and it is a real joy to own and operate one. One of the most satisfying experiences for a brewer is to create a great real ale and then invite friends over to pull pints off of the beer engine. It is a dangerously addictive practice.
As with any method of cask dispense, using a beer engine requires that the cask be vented to allow the beer to be pulled. The cask can be vented either by using a cask breather connected to a carbon dioxide tank or by allowing air into the cask as in the traditional approach. A cask breather is an extremely simple two-way valve that allows excess pressure in the cask to vent to the atmosphere and also allows one pint of carbon dioxide to be pulled into the cask when one pint of beer is pulled out. It in no way adds pressure or carbonation to the cask, but it does keep out air and its associated oxidative reactions.
Sample Recipe for Cask-Conditioned Ale
The following recipe is a good starting point for an authentic cask-conditioned ale.
Combine crushed malts and ~160 °F (~70 °C) water and gypsum. Hold at 152 °F (67 °C) for 1 hour. Lauter with 170–178 °F (77–81 °C) water, and collect ~6 gal in kettle. Boil down to 5.5 gal over 90 min. Chill and oxygenate. Pitch yeast and ferment. Rack into cask adding 0.25 cup boiled and cooled sugar and 0.5 oz East Kent Goldings hops in nylon hop bag. Allow to condition; vent excess CO2 and add finings. Let settle two days and serve.
Traditionalists — CAMRA in particular — believe that any real ale that is not dispensed by allowing air into the cask is not authentic real ale. Traditional cask-conditioned dispensing is an art involving careful attention to each beer’s unique characteristics of aging in the cask. Although the air allowed into the cask will have definite effects on the character of the beer — some of them desirable — brewers who use a breather can be sure of a cask that after several days is free from negative oxidation characteristics. My own advice is that if you are going to finish the cask in a few days, go ahead and follow tradition — otherwise, use a breather. Overtly oxidized beer is unwanted in any form of dispense.
Choosing a beer engine: Beer engines, both new and reconditioned, are available from several suppliers. When you get ready to order an engine, you must be prepared to make a few decisions. First, consider the size of the beer line that will deliver the beer into the engine. Sizes in the UK can be much larger than is typical in the United States. Get the size that will work for you.
Also, engines come in two basic dispense neck types: the swan neck (long or Northern neck) and the standard neck (short or Southern neck). In Britain, a huge debate rages over the question of what is the proper engine for serving various types of beers. Is it permissible, they wonder, to dispense the more highly carbonated, generally maltier Northern beers through a standard Southern neck, and the flatter, hoppier Southern beers through a Northern neck? Northern necks allow dispense of ales with slightly higher carbonation levels than Southern necks. Southern necks are designed to be used with very lightly carbonated ale, often found in the South. It is completely a matter of desired carbonation levels, and for this reason I usually recommend the purchase of a Northern neck. You can always serve a near-flat pint out of a long Northern neck, but it is harder to serve a more carbonated ale out of a short Southern neck.
To complicate matters, swan necks usually include a sparkler head (like a type of shower head) to knock carbon dioxide out of solution and leave a thick creamy head on top of the beer. It works along the same principle as a draught Guinness tap, forcing the beer through tiny holes and causing decarbonation.
Traditionalists will tell you that a hoppy beer forced through this kind of swan neck with a sparkler will lose all of its lovely hop aroma. As an avowed hophead, my experience has shown that the hop aroma is preserved quite well despite the use of a swan neck. The sparkler is omitted whenever the carbonation levels climb on the high side of the cask ale range, around 1.7 volumes; it generates too much foaming, and without a sparkler the beer still has a creamy head because of the higher carbonation level. Because I tend to serve my real ales slightly on the high side of the carbonation range, I dispense through a swan neck and usually without the sparkler. The hop aroma is consistently fantastic. Sparklers are removable, so you can always get one and experiment.
Finally, the bad news: Expect to pay about $ 400 for a new single engine or $ 200 for a reconditioned one.
Cask-conditioned ales are simple and rewarding, whether they be the fully traditional style or the keg-conditioned version. Cask ales allow for large degrees of experimentation with hops, yeast, and malts, and their low alcohol levels make them ideal session beers. With a little practice, top-notch cask ales can be made at home or in the brewpub and dispensed by gravity or with a beer engine.
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