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Club Yeast Bank
I have been yeast ranching for over 4 years (update: now over 9 years), maintaining my own yeast bank on slants that I purchased already prepared. Another member began doing so about a year ago, and we recently decided to solicit other members to join in to form a club yeast bank. We had 10 strains between us, and 3 other members contributed 10 more, for a total of 20. 9 other members joined, and each member keeps 3-6 of their most commonly used strains on slant in their personal bank. The two original ranchers will keep all strains on slant for the club bank (this is for redundancy & availability). Any member desiring one of the club strains has only to call one of the 2 members managing the bank, and within 2 days he has the desired strain.
I won't bore you with the details of how this came about, unless you choose to read it (just click here.) This page also contains the process for making slants.
We each have enough slants & wort tubes to keep us going for over 2 years, including reculturing unused strains every 6 months. We have these strains on slant (company names & numbers omitted for obvious reasons):
Creating a Yeast Starter
So, we came up with the following process to make it easy to make starters.
Items required:
- Screw cap test tube with 4 ml wort.
- Slant with sterile agar media.
- Slant with yeast.
- 2L Erlenmeyer flask (or other suitable container)
- 2 oz or 1/4 cup DME
- 1 sheet paper towel, folded and sprayed both sides with 70% alcohol
- 6" square of aluminum foil
- Magnetic Stir plate
- Teflon coated stir bar
During the process, whenever you open a tube it is a good practice to wipe the top of it, including the threads, with isopropyl alcohol. Try to keep them oriented near horizontal. Keep the cap from contacting anything by using your little finger curled around the cap to open it, then put the tube in the same hand. When you decant wort from the flask after refrigerating, wipe the lip of the flask both before and after with alcohol. You may want to set up a small propane torch and also flame the lip of the tubes & flask whenever necessary. The torch will also provide an updraft, so keeping your work close to the torch will minimize the possibility of any nasty critters falling into your tubes or flask.
Process:
- Brewday - 5: Pour the wort from the test tube into the yeast slant. Leave 2 days with cap loosened to relieve pressure.
- Brewday - 3: Make up 1 L wort using 2 oz or 1/4 cup DME in 1 L water (or use pre-canned wort). Boil 20 min in flask with aluminum foil wrapped over the top. Chill in a sink of cold water. Meanwhile, flame an innoculation loop, dip into the culture slant, and innoculate a fresh slant for storage. Pour contents of slant (just the wort - not the agar) into the flask and put on it on the stir plate. Cover with a folded paper towel that has been sprayed on both sides with alcohol and secure with a rubber band. Cover loosely with a piece of sanitized aluminum foil, allowing for exposure to air of the edges of the paper towel. Stir at high speed for 2 days.
- Brewday - 1: Put the flask in the fridge the night before brewing.
- Brewday - 0: Take it out of the fridge, wipe the mouth of the flask with alcohol & flame it, and pour out the liquid to leave the slurry behind. Make up another liter of wort (using pan or another flask), chill, and add to the flask. Stir only long enough to mix well, and then let grow naturally. By the time you are ready to pitch it will be at high krausen.
Alternatively, and this is often what I do, add the first liter of runoff from your chilled wort into the flask. Let this go for a few hours before pitching into the fermenter.
That's all there is to it! 2 minutes on brewday - 5, then about a half hour on brewday - 3. I add one more step (1 day, 1 liter) if I'm doing a 10 gallon batch, or a lager. I'll repeat again for 10 gallon batches of lager.
| Strains in the club Yeast Bank |
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| Strain | Description | Attenuation | Flocculation | Optimum
Temperature |
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| Ale Strains |
| American Ale (1056) | Very clean crisp flavor characteristics. Low fruitiness and mild ester production. Slightly citrus like with cool 60-66º F, (15-19º C) fermentation temperatures. | 73-77% | low to medium | 60-72° F |
| American Ale ll (1272) | Fruitier and more flocculant than 1056, slightly nutty, soft, clean, slightly tart finish. | 72-76% | high | 60-72°F |
| Bavarian Weizen (300) | 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. | 73-77% | low | 64-75°F |
| Belgian Ale (500) (Chimay) | From one of the six Trappist breweries remaining in the world, this yeast produces the distinctive fruitiness and plum characteristics. Excellent yeast for high gravity beers, Belgian ales, dubbels and trippels. | 73-78% | low / med | 65-72°F |
| Belgian Ale (550) | Saisons, Belgian Ales, Belgian Reds, Belgian Browns, and White beers are just a few of the classic Belgian beer styles that can be created with this yeast strain. Phenolic and spicy flavors dominate the profile, with less fruitiness then WLP500 (1214). | 72-78% | medium | 68-78°F |
| Belgian Strong Ale (1388) | Robust flavor yeast with moderate to high alcohol tolerance. Fruity nose and palate, dry, tart finish. | 73-77% | low | 65-75°F |
| European Ale (1338) | From Wissenschaftliche in Munich. Full-bodied complex strain finishing very malty. Produces a dense, rocky head during fermentation. | 67-71% | high | 62-72°F |
| Irish Ale (1084) | Slight residual diacetyl and fruitiness; great for stouts. Clean, smooth, soft and full-bodied. | 71-75% | medium | 62-72°F |
| Kolsch (2565) | A hybrid of ale and lager characteristics. This strain develops excellent maltiness with subdued fruitiness, and a crisp finish. Ferments well at moderate temperatures. | 73-77% | low | 56-64°F |
| London Ale (1028) | Rich with a dry finish, minerally profile, bold and crisp, with some fruitiness. | 73-77% | medium | 60-72°F |
| London Ale lll (1318) | From traditional London brewery with great malt and hop profile. True top cropping strain, fruity, very light, soft balanced palate, finishes slightly sweet. | 71-75% | high | 64-74°F |
| London ESB Ale (1968) | Highly flocculant top-fermenting strain with rich, malty character and balanced fruitiness. This strain is so flocculant that additional aeration and agitation is needed. An excellent strain for cask-conditioned ales. | 67-71% | high | 64-72°F |
| Saison Ale (565) | Classic Saison yeast from Wallonia. It produces earthy, peppery, and spicy notes. Slightly sweet. With high gravity saisons, brewers may wish to dry the beer with an alternate yeast added after 75% fermentation. | 65-75 | medium | 68-75 |
| Scottish Ale (1728) | Ideally suited for Scottish-style ales, and high gravity ales of all types. | 69-73% | high | 55-70°F |
| Trappist High Gravity (3787) | 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. | 75-80% | medium | 64-78°F |
| Lager Strains |
| Bavarian Lager (2206) | Used by many German breweries to produce rich, full-bodied, malty beers. Good choice for Bocks and Dopplebocks. | 73-77% | medium | 46-58°F |
| Bohemian Lager (2000) | Very malty. Low sulfur. The yeast used by the original Budweiser brewery in the Czech Republic. Available exclusively through St. Pats. | 67-71% | medium | 46-52°F |
| California Lager (2112) | Particularly suited for producing 19th century-style West Coast beers. Retains lager characteristics at temperatures up to 65° F, (18° C) and produces malty, brilliantly clear beers. | 67-71% | high | 58-68° F |
| Czech Pils Lager (2278) | Classic pilsner strain from the home of pilsners for a dry, but malty finish. The perfect choice for pilsners and bock beers. Sulfur produced during fermentation dissipates with conditioning. | 70-74% | med / high | 48-58°F |
| Danish Lager (2042) | Rich, dortmund-style, crisp, dry finish. Soft profile accentuates hop characteristics. | 73-77% | low | 46-56°F |
| German Bock Lager (833) | From the alps of southern Bavaria, this yeast produces a beer that is well balanced between malt and hop character. The excellent malt profile makes it well suited for Bocks, Dopplebocks, and Oktoberfest style beers. Very versatile lager yeast, it is so well balanced that is has gained tremendous popularity for use in Classic American style Pilsners. Also good for Helles style lager beer. | 70-76 | medium | 48-55°F |
| Munich Lager (2308) | A unique strain, capable of producing fine lagers. Very smooth, well-rounded and full-bodied. Benefits from temperature rise for diacetyl rest. | 73-77% | medium | 48-56°F |
| Other Strains |
| Champagne Yeast (715) | Classic yeast, used to produce champagne, cider, dry meads, dry wines, or to fully attenuate barley wines/ strong ales. Can tolerate alcohol concentrations up to 17%. Neutral. | >75% | low | 70-75°F |
| Sweet Mead/Wine Yeast (720) | A wine yeast strain that is less attenuative than WLP715, leaving some residual sweetness. Slightly fruity and will tolerate alcohol concentrations up to 15%. A good choice for sweet mead and cider, as well as Blush wines, Gewürztraminer, Sauternes, Riesling. | <75% | low | 70-75°F |
In May, 2002, luminaries from the Siebel Institute graciously agreed to field questions from readers of the Homebrew Digest. I posted a query, explaining my procedure and asking some questions asking their opinions of the procedure. Here is the response:
Date: Wed, 15 May 2002 19:29:05 +0000
From: mailto:fischborn@hotmail.com
Subject: Siebel Response: Yeast propagation
Steve asked......
Date: Fri, 10 May 2002 10:41:10 -0400
From: "Jones, Steve (I/T) - Eastman"
Subject: Siebel Week: Yeast propagation
First, thanks to you all for fielding our questions.
I've been yeast ranching for about 4 years now, and have recently modified my process to make it easier. I have acquired a stir plate, and made up a quantity of 10 ml tubes with agar, and a like number with 4 ml wort. The agar was made using 350 ml water, 10 gr DME, 5 gr Agar flakes, and 1 gr Yeast Nutrient. All were autoclaved. I have 20 strains on slant, and here is my process to grow enough yeast for 10 gallons of wort:
Evening 1:
Agitate tube containing 4 ml wort to aerate. Add to the agar slant containing the yeast. Allow to grow 2 days.
Evening 3:
Boil 2 oz DME and 1 liter water in a 2L flask for 20 minutes, chill in sink. I prepare a work space by suspending a 2' x 2' piece of cardboard about 18" above a countertop, and misting the area with isopropyl alcohol. Then I dip a flamed inoculation loop into the slant and inoculate a new slant. Pour contents of slant with yeast into the flask. Place on stir plate at highest setting and run continuously.
Evening 5:
Refrigerate flask
Morning 6 (brewday):
Make up another liter of wort as above, or use wort previously pressure canned for this purpose. Decant most of the liquid from the culture and add the fresh wort. Place on stir plate just long enough to mix well. Pitch into fermenters about 6 hours later. For lagers, repeat day 3 & 5 to increase quantity of yeast.
I grow the inoculated slant for about 3-6 days at room temp until a good layer of yeast is visible, then refrigerate for future use. I figure that this qualifies as 'reculturing' the slant to make it good for another 6 months. Every 6 months I reculture the slants that weren't used the last 6 months. I don't perceive any negative affects since I changed my process, and generally make pretty decent beer, but I still have a few questions:
1. Does the fact that I use a stir plate negate the drawbacks of stepping up from 4 ml to 1000 ml?
Forbes: Perhaps, especially as you give it two days. Propagation of yeast is often okay with an inoculation as small as a 50th or 100th of the new volume, but normally we would not go further than that
2. Does the process of decanting the liquid and adding fresh wort remove the chances of harming my beer by adding oxidized starter wort? Is this necessary?
Tobias: Decanting the liquid is good. The "propagation" wort is not only oxidized but contains all the undesirable flavours(higher alcohols, esters...), which are produced at forced fermentations.
3. Can I extend the time for reculturing past 6 months? How long until there is danger of mutation?
Forbes: If you are only keeping your slants refrigerated then 6 months is normally the maximum time you would like to leave before re-freshing your stock.
4. Am I introducing any unforeseen factors that may have a negative impact on my beer?
Tobias: No, your system looks fine, as long as you take all measures to avoid contaminations.
5. I have had trouble retaining the banana/clove characteristics of the Weihenstephan weizen yeast from a slant. Is this normal? If not, what might I be doing wrong?
Tobias: No, this is not normal!!! The yeast should keep its ability to produce banana/clove flavour. During my time in Weihenstephan I was responsible for the culture collection and we never noticed this with the yeast. You will not necessarily smell it on the slant but you should smell it in your fermentation.
6. I've found this to be much easier and less time-consuming than the normal process of stepping up thru 10x increases. What is your overall opinion of this process?
Forbes: To me your process is okay. The less chance you have for contamination the better, but you seem to be very aware of this fact.
I am going to take these answers as an affirmation of my process.
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