Brewing: Yeast Starters

Posted on 12.11.07 8:18PM under Brewing, Yeast

Brewer's Yeast CellsI have already talked about the basics of brewing typical beer, both with malt extracts and directly using malted grains. I’m going now to go a bit into more detail about one pretty easy way to improve your brewing.

When you normally pitch yeast directly from a package that you get at the homebrew shop, often times there is just enough yeast to be minimally adequate to ferment an average strength wort – say 1.060 or less. Once you want to make beers with more alcohol, the prepackaged doses of yeast may not be enough to give a vigorous start, thorough fermentation, and minimize undesired byproducts of excessive yeast growth.

To determine the recommended pitching rate for yeast, use software! Jamil Zainasheff has perhaps the most recommended yeast pitching rate calculator. This guy has won lots of awards for his beers and writes for the big homebrew magazines, so I would tend to believe he knows what he’s talking about.

For most bigger beers, a small starter of a few quarts is good enough. It is at least better than no starter at all. Normally a starter is about a cup of DME per quart of water, which will give you a starting gravity around 1.040. You want a small beer (that is, low gravity) for this purpose so that you don’t strain the yeast too much. You want them to be able to grow and multiply freely and be ready to rock when they’re done with the starter you’ve given them. Hops are optional. It is very interesting to make beer with just DME and yeast. You really get a sense for the flavor of the yeast you’re using when there’s nothing else in there to compete with the flavor. You can use hops to make the starter a more potable beverage. It is fun to drink the starter while you make the main beer. Sort of feels like a sacrifice to the yeast gods somehow.

There are different opinions about the timing of the yeast starter. Some say to pitch the yeast starter when it is at its peak of working – about two days after making it, depending on many factors. Others say just go ahead and let it complete, then pitch. I have personally never had enough confidence in my timing abitlities and scheduling limitations to even plan on pitching a starter at full activity. I like to just let them finish, and then pitch them. The night before brewing, I put the starter batch in the fridge to crash cool it to get as much yeast out of suspension as possible. Then the morning of brewing, I just gently pour as much of the liquid off the top (into a pitcher for serving) as I can. Then what’s left is a bunch of yeast at the bottom of the jug and just enough liquid to create the perfect viscosity for pouring. Then I put the sanitary airlock back on the starter and let it sit and get back to fermenting temperature. Finally, pitch as normal after cooling freshly brewed wort.

It just so happens that today I made a monstrous “yeast starter”. It is a full five-gallon all-grain batch of beer: hops, irish moss, the whole nine yards. The recipe is here. The OG is about 1.045 (intended a bit lower), and I am really looking forward to having some low octane beer around to hang out with the big bad monsters I’ve got in the fridge now in this season of Barley Wines. I’ve never done a full batch starter and pitched using yeast cake, so it should be interesting to see how it comes out.

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