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Talks with the Geeks &
Gurus...
In this monthly feature we'll give you as much practical, (and maybe some extraneous), information about yeast as possible... Hopefully it'll answers your questions to the fullest! This month we look at the commercially available Wyeast cultures. These are the most up to date descriptions we could get from their laboratories. Yeast Characteristics of the popular Y-yeast (liquid cultures) ***Profiles and average fermentation characteristics of each yeast strain. 1OO7 German ale yeast. Ferments dry and crisp, leaving a complex but mild flavor. Produces an extremely rocky head and ferments well down to 55* F. Flocculation - low; apparent attenuation - 73-77%. (55-66* ) 1028 London ale yeast. Rich, minerally profile, bold and crisp, with some diacetyl production. Flocculation - medium; apparent attenuation - 73-77%. (60-72* F) 1056 American ale yeast. Used commercially for several classic American ales,(Sierra Nevada). This strain ferments dry, finishes soft, smooth and clean, and Is very well balanced. Flocculation low to medium; apparent attenuation 73-77%. (60-72* F). 1084 Irish ale yeast. Slight residual diacetyl and fruitiness; great for stouts. Clean, smooth, soft and full-bodied. Flocculation - medium; apparent attenuation - 71-75%. (62-72* F) 1098 British ale yeast. (From Whitbread). Ferments dry and crisp, slightly tart, fruity and well-balanced. Ferments well down to 65*F. Flocculation - medium; apparent attenuation - 73-75%. (64-72* F) 1272 American ale yeast II. Fruitier and more flocculent than 1056, slightly nutty, soft, clean, slightly tart finish. Flocculation - high; apparent attenuation - 72-76%. (60-72* F) 1275 Thames Valley ale yeast. Produces classic British bitters, rich complex flavor profile, clean, light malt character, low fruitiness, low esters, well-balanced. Flocculation medium; apparent attenuation - 72-76%. (62-72* F) 1335 British ale yeast II. Typical of British and Canadian ale fermentation profile with good flocculating and malty flavor characteristics, crisp finish, clean, fairly dry. Flocculation - high; apparent attenuation - 73-76%. (63-75* F) 1318 London ale yeast III. From traditional London brewery with great malt and hop profile. True top cropping strain, fruity, very light, soft balanced palate, finishes slightly sweet. Flocculation - high; apparent attenuation - 71-75%. (64-74* F) 1728 Scottish ale yeast. Ideally suited for Scottish-style ales, and high-gravity ales of all types. Gives some vinous flavors. Flocculation - high; apparent attenuation 69-73%. (55-70* F) 1338 European ale yeast. From Wissenschaftliche in Munich. Full-bodied complex strain finishing very malty. Produces a dense, rocky head during fermentation. Flocculation - high; apparent attenuation - 67-71%. (60-72* F) 1214 Belgian ale yeast. Abbey-style top-fermenting yeast, suitable for high-gravity beers. Estery. Flocculation medium; apparent attenuation - 72-76%. (58-68* F) 1388 Belgian strong ale yeast. Robust flavor yeast with moderate to high alcohol tolerance. Fruity nose and palate, dry, tart finish. Flocculation - low; apparent attenuation 73-77%. (65-75* F) 1742 Swedish ale yeast. Stark beer Nordic- style yeast of Scandinavian origin, floral nose malty finish. Flocculation medium; apparent attenuation - 68-72%. (64-74' F) A.K.A. 1187. 1762 Belgian Abbey Yeast II. High gravity yeast with distinct warming character from ethanol production. Slightly fruity with dry finish. Flocculation - medium; apparent attenuation - 73-77% (65-75* F) 1968 London ESB ale yeast. Highly flocculent top-fermenting strain with rich, malty character and balanced fruitiness. This strain Is so flocculent that additional aeration and agitation is needed. An excellent strain for cask-conditioned ales. Flocculation - high; apparent attenuation - 67-71%. (64-72* F) 2565 Kölsch yeast. A hybrid of ale and lager characteristics. This strain develops excellent maltiness with subdued fruitiness, and a crisp finish. Ferments well at moderate temperatures. Flocculation - low; apparent attenuation - 7377%. (56-64* F) 1087 Wyeast ale blend. A blend of the best ale strains to provide quick starts, good flavor and good flocculation. Apparent attenuation - 71-75%. (64-72* F) 3278 Belgian Lambic blend. Belgian Lambic-style yeast blend with lactic bacteria. Rich earthy aroma and acidic finish. Suitable for gueze, fruit beers and faro. Flocculation - low to medium-, apparent attenuation - 65-75%. (63-75' F) 2007 Pilsen lager yeast. A classic American pilsner ,strain, smooth, malty palate. Ferments dry and crisp. Flocculation - medium; apparent attenuation - 71-75%. (48-56* F) 2035 American lager yeast. Not a pilsner strain. Bold, complex and aromatic, producing slight diacetyl. Flocculation - medium; apparent attenuation - 73-77%. (48-58* F) 2042 Danish lager yeast. Rich, Dortmund-style, crisp, dry finish. Soft profile accentuates hop characteristics. Flocculation - low; apparent attenuation - 73-77%. (46-56* F) 2112 California lager yeast. Particularly suited for producing 19th century-style West Coast beers. Retains lager characteristics at temperatures up to 65' F, and produces malty, brilliantly-clear beers. Flocculation - high; apparent attenuation - 67-71%. (58-68* F) 2124 Bohemian lager yeast. A pilsner yeast from Weihenstephen. Ferments clean and malty, with rich residual maltiness in full gravity pilsners. Flocculation - medium; apparent attenuation 69-73%. (46-54* F) 2206 Bavarian lager yeast. Used by many German breweries,(thought to be Spatens) to produce rich, full-bodied, malty beers. Flocculation: medium; apparent attenuation 73-77%.(48-58* F) 2247 Danish lager yeast II. Clean dry flavor profile often used in aggressively hopped pilsner. Clean, very mild flavor, slight sulfur production, dry finish. Flocculation - low; apparent attenuation - 73-77%. (46-56* F) 2272 North American lager yeast. Traditional culture of North American and Canadian lagers and light pilsners. Malty finish. Flocculation - high; apparent attenuation 70-76%. (48-56* F) 2278 Czech pils yeast. Classic pilsner strain from the home of pilsners; for a dry, but malty finish. The good choice for pilsners and bock beers. Sulfur produced during fermentation dissipates with conditioning. Flocculation medium to high; apparent attenuation - 70-74%. (48-64* F) 2308 Munich lager yeast. A unique strain, capable of producing fine lagers. Very smooth, well-rounded and full-bodied. Flocculation - medium; apparent attenuation 73-77%. (48-56* F) 2178 Wyeast lager blend. A blend of the Brewer's Choice lager strains for the most complex flavor profiles. Apparent attenuation - 71-75%. (48-56* F) 3068 Weihenstephan weizen yeast. Unique top-fermenting yeast which produces the unique and spicy weizen character, rich with clove, vanilla and banana. Best results are achieved when fermentations are held around 68* F. Flocculation - low; apparent attenuation - 73-77%. (64-70* F) 3056 Bavarian wheat yeasts. Blend of top-fermenting ale and wheat strains producing mildly estery and phenolic wheat beers. Flocculation - medium; apparent attenuation - 73-77%. (64-70* F) 3333 German wheat yeast. Subtle flavor profile for wheat yeast with sharp tart crispness, fruity, sherry-like palate. Flocculation - high; apparent attenuation - 70-76%. (63-75* F) 3787 Trappist high gravity. Robust top cropping yeast with phenolic character. Alcohol tolerance to 12%. Ideal for Biere de Garde. Ferments dry with rich ester profile and malty palate. Flocculation - medium; apparent attenuation 75-80% (64-78* F) 3942 Belgian wheat beer. Estery low phenol producing yeast from small Belgian brewery. Apple and plum like nose with dry finish. Flocculation: medium; apparent attenuation - 72-76%. (64-74* F) 3944 Belgian Witbier yeast. A tart, slightly phenolic character capable of producing distinctive witbiers and grand cru-style ales alike. Alcohol tolerant, Flocculation - medium; apparent attenuation - 72-76%. (60-75* F)
3021 Prisse de mousse, Institute Pasteur champagne yeast race bayanus. Crisp and dry, ideal for sparkling and still white wines and fruit wines. Low foaming, excellent barrel fermentation, good flocculating characteristics. Ferments well at low (55-65* F) temperatures. Can be used for high-gravity beers. Attenuation high. 3028 French (Bordeaux) wine yeast. Ideally suited for red and white wines which mature rapidly or bigger reds requiring aging. Moderate foaming, low sulfur production over a wide temperature range. Enhances the fruity characteristics of most wines. Attenuation medium. (65-90* F) 3134 Sake yeast. For use in conjunction with koji in the production of a wide variety of Asian jius (rice-based beverages). Full-bodied profile with true sake character. (65-75* F) 3184 Sweet mead yeast. Top-fermenting yeast which leaves residual sugar after fermentation. Needs nutrient added to mead. Attenuation low. (65-75* F) 3632 Dry mead yeast. Classic mead yeast for a dry finish. Low-foaming with little or no sulfur production. Attenuation high. (55-75* F) 4007 Malo-lactic culture for winemaking. Leuconostoc oenos blend isolated from western Oregon wineries. Includes strains Ey2d and Erla. Excellent for high acid wines and low pH. Softens wines by converting harsh malic acid to milder lactic acid. Can be added to juice any time after the onset of yeast fermentation when sulfur dioxide is less than 15 ppm. (55-75* F)
One of the main features that distinguishes beer from all other beverages is its ability to pour a nice thick, foamy head. Indeed, without those millions of tiny bubbles, a beer would seem lifeless and dull. When beer is properly carbonated it will most fully express its aromatic qualities and it will tingle and effervesce in the mouth. To better understand this crucial element of beer, we should examine just exactly where all those bubbles are coming from. Yeast is the life force in beer. When yeast is pitched into brewer's wort it feeds upon sugars and gives off equal parts of alcohol and carbon dioxide (CO2). The amount of C02 given off by fermentation is considerable. Most of this is simply vented off the top of the fermenting vessel (except in large breweries where it is collected, cleaned, compressed into a liquid and stored for later use). To carbonate their beer, brewers have a variety of techniques available. This article will discuss the following methods: bottle conditioning (priming), spunding, kraeusening, and force carbonating. One of the oldest methods of carbonating is called priming. This traditional ale making method involves letting the beer ferment out and then racking it into kegs or casks. At this point a small dose of sugar is added to each cask. The remaining yeast in the beer ferments this sugar and the beer retains the C02 generated. Priming is also the most popular carbonating method with home brewers, especially those just beginning to home brew. The normal recommendation is for 2/3 cup of corn sugar to prime 5 gallons of beer, (editor's note: some guides will say up to 3/4 cup of corn sugar to prime; experience dictates closer to 2/3 cup for proper carbonation levels). The sugar is mixed into the beer just prior to bottling. After 2 to 4 weeks in the bottle, the beer is usually ready to drink. Those who age their beer for extended periods before bottling can run across the problem of having very little active yeast left over to prime the beer properly. Beers over 8% alcohol can have this problem also. The solution is to pitch a small dosage of new yeast along with the priming sugar. This yeast does not have to be the same strain used in fermentation. Lager yeasts are sometimes used for bottle conditioning because they tend to flocculate better than ale strains. One of the greatest advantages of bottle conditioned beers is their potential shelf life. Provided they are properly handled, beers with active yeast in the bottle can continue to mature and develop for months or even years. Filtered beers do not have this advantage. Bottle conditioning is no guarantee of long term stability, however. Excessive amounts of trub or non-viable yeast cells in the bottle can lead to adverse flavor changes and actually shorten the potential shelf life. For this reason most commercial breweries will filter their beer after aging and then pitch a known quantity of priming sugar and yeast immediately prior to bottling. This helps ensure that the product will be fairly clear in the bottle and that the amount of sediment will be within reasonable limits. Indeed, when properly performed, this procedure can give such low amounts of sedimented solids that the consumer might be unaware that the beer is bottle conditioned. The ales from Sierra Nevada Brewing Company are a good example of this procedure. Another method of carbonation is called spunding (sometimes referred to as bunging). In a single tank system this method simply involves closing the tank vent when fermentation is within 1% Plato (.004 gravity points) of its completion. The remaining C02 generated is retained in the tank and absorbed into the beer. In a multi tank system the beer is fermented down to within 1.0-1.5% P of its target gravity (usually in an open fermenter) and then transferred to the secondary fermentation vessel which is capable of holding pressure. A disadvantage of this method is that by removing the beer from its yeast bed an incomplete attenuation can result. This is normally offset by the rousing of the yeast caused by the turbulence of transfer. Home brewers should simply make sure they siphon up a bit of the yeast bed during transfer. Obviously, spunding is most commonly used by lager brewers. The slow fermentation times of lager beers make it easy to predict when the desired Plato reading will be reached. Some breweries might have lager beers usually show a drop of 1% P per day for the last 3 or 4 days of fermentation. Ales, on the other hand, will sometimes drop 2 to 3 % P within an 8 hour period. For the home brewer the same rules apply. Spunding would be most practical for someone who brews lagers in 5 or 10 gallon soda kegs. When the fermentation is near completion the vent should be, closed.. and a pressure gauge attached to the gas inlet connection. This will allow monitoring of the pressure build up. Most soda kegs will hold up to 130 psi but if you should ever find yourself with 30 or so pounds of pressure in your tank after spunding you will know that something has gone wrong. Commercial breweries have pressure relief valves set at 12 to 15 psi to prevent this. The home brewer will have to do this manually unless some sort of relief valve is incorporated onto the keg. Under no circumstance should this method ever be attempted with glass carboys or any other non pressure rated vessel! Another method commonly used in lager breweries is kraeusening. This involves letting the beer ferment itself out completely before transferring to a lager tank. In the lager tank an addition of 10 to 20% new beer in high fermentation is introduced. As this additional beer ferments out the C02 generated is absorbed and carbonation is achieved. One of the main advantages of this method is that by blending between batches greater uniformity is assured. A major disadvantage is that the introduction of new beer into older beer can impart a "green beer" flavor which requires additional lagering time to be reduced. The home brewer can utilize kraeusening more readily than spunding. Because the beer is fermented to completion, this method can also be used for ales. The only drawback is that one needs to brew an identical or very similar style of beer to act as the kraeusening agent. One way to avoid this problem is by putting some unfermented wort aside and reintroducing it into its - parent batch after primary fermentation. Charlie Papazian covers this well in his book The New Complete Joy of Home Brewing, as does Douglas Serrill in zymurgy vol. 16, no. 5 (Winter 1993). They cover the appropriate calculations for the amount of wort to set aside. Usually it is about one quart for every five gallons of beer. The problem with this approach is the possibility of contamination from the storing of unfermented wort and its subsequent addition to the main batch of beer. Most home brewers get the best results by keeping beer transfers to a minimum, thus avoiding oxidation problems and possible microbial infection. With the foregoing in mind, it is appropriate to consider a couple of final carbonation techniques. Force carbonation, as the name implies, involves forcing C02 gas into flat beer. Commercial breweries use a carbonating stone made of porous rock or sintered stainless steel to diffuse the gas into millions of tiny bubbles which are readily absorbed by the beer. The gas absorbs much more readily at colder temperatures. Trying to force up warm beer usually results in a foamy mess. [Keg beer usually is best at 2.4 to 2.6 volumes, bottles at 2.7 to 2.9]. Home brewers can force carbonate by racking their beer into a soda keg and then vigorously agitating the keg while forcing C02 into it. A more refined approach is to fit an aquarium aerating stone inside a keg. This serves as an effective C02 diffuser and can save your back the hassle of shaking kegs. To demonstrate the ease of force carbonation we will take 5 gallons of beer that is flat and force it up to a proper dispensing level. The procedure is as follows: 1. Sanitize carbonation tank and
purge with C02. 1. Sanitize carbonation tank and
purge with C02. As an aside, an additional benefit of a carbonating stone is the ability to scrub unwanted volatile aromas from your beer. For example, if you made a Pale ale and threw in a few too many handfuls of Cascade hops at the end you do not have to live with a beer that smells like grapefruit. Just turn on the C02 stone and leave the top vent open for a few minutes. The stream of gas rising through the beer will scrub out much of that overly hoppy aroma. Sorry, but it will not do anything about oxidation problems.
"Fridge hah!...It carbonates easily all year up here" Finally, a less glamorous method of force carbonating is to simply apply about 10 pounds of top pressure on 32 degree F. beer and wait. After a few weeks it will absorb all of the available C02. The greater the surface area exposed to C02, the more rapidly this will occur. Good Luck, and Happy Carbonation ... Prost!
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