Starter Cultures for Beer Yeast: A How-To Plan
OK, most of the yeast packets you will buy, especially the Wyeast smack packets, do not contain enough yeast to get a fermentation going as aggressively as you would want it to. The White Labs are a little better, but sometimes you just really want a good kick-butt fermentation that starts within a few hours - as opposed to a few days!
The benefits of a starter culture are several-fold:
- bacteria are basically overwhelmed by the "army" of yeast that you have produced, making sterilization not QUITE as important (although always sterilize everything, trust me!!)
- oxidizing the wort before the yeast go in is very important for the growth of the developing yeast - but it is never done as much as you really should - on the homebrewing level it is very difficult to maximize your (healthy) oxygenation. Starter cultures lower this need, as the yeast have already gone through major growth stages prior to hitting your five gallons.
- high-gravity beers almost always need big starter cultures in order to achieve decently-low-enough final gravities - without them, these beers tend to "stall" while they are still sweet and "worty" - any beer that starts over 1.070 should have a starter done to it.
- many beers will achieve better final gravities as well, not only "big" beers
- it brings peace of mind to the brewer to see a beer fermenting five hours after he brings it off the boil, as opposed to 36 or 40 hours.
OK, now here is the way that I recommend you do a starter culture - this is not the only way, so don't hate-mail me with all of your alternatives, but this makes a pretty darn good starter.
Make the starter to the same gravity as the beer you are intending to brew. This is basic genetic selective breeding. You do not want to make a 1.025 gravity starter, and develop yeast that are most happy in this medium, only to pitch them into a 1.090 beer, which they "genetically" hate. Make your starter to match your brew. One pound of dried malt extract - which is the easiest malt to measure - in one gallon of water will make about a 1.045 gravity. If you have a normal strength beer, this means that one-half pound in one-half gallon will be 1.045, or one quarter pound in one quart of starter will be 1.045.
OR one pound of dried malt extract in one-half gallon of starter would be 1.090, or one half pound of dried malt in one quart would be 1.090 - get it? It's basic pro-rating.
I recommend, volume-wise, a one-half gallon (that equals two quarts) of starter - I have not seen enough benefit (for the same work it takes) to do a 22 ounce bottle of starter. Just do a big one, it will be the same time and energy and much more beneficial. (And you don't "lose" the starter - it winds up in your beer anyway....)
So here's the process: take just under three quarts of water, add your DME (one half to one pound, depending on your target gravity) and bring to a boil - be careful of foam-overs!!! Add a "pinch" of hops for the anti-bacterial effects. Bring to a boil and boil for about fifteen minutes, uncovered. Strain out the hops, and re-boil for five minutes to re-sterilize the wort. Take off the heat, cover and cool as fast as possible. I sink my pot in an ice bath. When chilled, add the wort to a gallon glass jug, add your yeast and airlock it.
It will start fermenting within 12 - 20 hours, and go for about two to four days. You can use it anytime during this cycle and you can add all of the wort (as I do) or wait till the yeast settles, then pour off the starter wort, adding only the settled yeast to the five gallon batch that you cook up AFTER THE STARTER IS READY.
You will like the efects - beers come out cleaner and tastier, and I highly recommend it. Call or e-mail with questions.