You Do Use Yeast Starters, Right?

5/23/08

One of the secrets to making great beer is pitching the proper amount of healthy, active yeast. When you underpitch, the yeast can become stressed, producing unwanted off flavors in the form of excess esters. In addition, underpitching results in a longer fermentation lag time, giving any bacteria, fungi, or wild yeast present in your wort a chance to take over and ruin your beer.

Making a starter is a great way to propagate strong, healthy yeast cells that will be ready to get to work as soon as you pitch them into your wort. Both Wyeast and White Labs sell liquid yeast in packages they claim contain a sufficient cell count to ferment a standard five gallon batch. This is true – if you pitch a smackpack or vial of yeast directly into your wort, it will ferment and you’ll make beer. However, you may not be making the best beer possible, and that’s what this website is all about.

A starter also verifies that the yeast you are using is viable. This is essential if you are pitching an older smackpack or vial, but it’s a good idea to verify viability even with newer packages. You don’t know what kind of shipping conditions that pack went through between the lab and your hands – imagine spending hours brewing up a batch of what will be some awesome beer, pitching your yeast, and then…nothing. The horrible feeling of a stalled fermentation, racing around for replacement yeast, and crossing your fingers to ward off infection are not something I would wish on any brewer.

Need more convincing? Better brewers than I have written volumes on the subject. Check out Jamil Zainasheff’s must-read article on starters. The man speaks with the weight of two Ninkasi Awards around his neck – I’m sure listening. Jamil also has a great resource on his website – the Yeast Pitching Rate Calculator. This handy tool will help you decide exactly how much yeast you need given the OG of the beer you are planning to brew and the freshness of the yeast you are using.

So what is a starter? Basically, it’s a mini-batch of wort you brew to feed the yeast – to get them awake, active, and propagated to the right numbers to ferment your beer. The starter wort should be between 1.030 and 1.040 OG, regardless of the OG of the beer you plan to pitch the yeast in. The starter wort doesn’t need any hops or additives, with the exception of yeast nutrient (available at homebrew shops). Starters are typically made with DME (it’s easy), but there’s no reason you couldn’t mash a small amount of base malt to get the starter wort if you really wanted to. Seems like way too much work to me – I just keep a few bags of DME on hand and I’m set.

Now that you’re (hopefully) on the starter bandwagon, let me say that starters are not always recommended. The important thing to remember is you want to pitch the proper amount of yeast – overpitching can be just as bad as underpitching. For a very small batch or a beer with a very low OG, a smackpack or vial might provide enough yeast on its own. The best way to determine if you need a starter (and the size of the starter if you do) is to do the math and figure out how many cells you need to pitch. Luckily, Jamil’s Pitching Rate Calculator makes this as easy as clicking your mouse, and you can also calculate the proper amount of dry yeast or slurry if that is what you are pitching (starters are not normally used if you are pitching dry yeast. Dry yeast is so inexpensive it usually makes more sense to just buy more packs if you need).