Some Notes about Yeast

I wanted to write down some notes about brewer's yeast.

Safale US-05

US-05 is the only dry yeast that I've found so far that's really worth using. It has a very clean and neutral flavor, suitable for using in something like an IPA. Plus, Fermentis gives you 200 billion cells in US-05, which means that you don't need more than one packet for an average gravity beer.

US-05 contains "Chico" yeast. Chico is a famous strain that is widely used in the United States. For example, New Orleans Brewing (NOLA) uses Chico heavily, as does Fieldworks Brewing. You can get Chico in liquid form, but I never was able to tell the difference, and the dry form is cheaper and easier.

Chico is kind of a freak among brewer's yeasts. First of all, it has only two chromosomes, whereas most brewer's yeasts have many more. This apparently makes it more likely to mutate over time. I haven't personally experienced this since I don't usually repitch more than once or twice, but apparently it's a concern.

Another interesting thing about Chico is that it can ferment ales at a cold temperature-- all the way down to 50F, in fact. Most ale yeasts start having trouble below 60F, but Chico keeps on going. Chico also tends to do better at hot temperatures (above 75F) than many other strains. In general, Chico seems to be very forgiving about fermentation temperature. If your homebrewing setup doesn't have good temperature control, this is probably the yeast for you.

Is Chico completely neutral? Well... not completely. Apparently if you ferment below 65F, Chico produces some an ester named linalyl formate. Some people perceive this as a peachy flavor. This may or may not match with the beer you are trying to brew.

In general, I raise my glass to US-05, the only dry yeast worth knowing about.

Safale US-04

I used to use US-04 a lot. Fermentis describes it as an "English ale yeast." However, all of my attempts to produce an English ale with US-04 have proved disappointing.

One of my friends was trying to put his finger on the reason why the beer was disappointing. He said, "it has this weird sweet point." I definitely agree with that-- US-04 does make beers taste sweet. Strangely enough, it does this despite the fact that it generally produces an extremely high attenuation. Fermentis claims that the attenuation goes up to 75%, but I've definitely seen more than 80% attenuation with this strain. US-04 also seems to have an unpleasant bready flavor.

Eventually I stumbled across some information about this yeast strain online. The strain is named Whitbread B. The old Whitbread brewery used to use this in their "tower fermenters." Tower fermenters are basically huge towers where you put wort in one end, and scoop beer out the other. It's a continuous process, rather than a batch process like the fermentations we know and love.

I learned that Whitbread B produces lactic acid during fermentation. The end result is a little bit like squeezing a lemon into your beer. It's a tart flavor that tends to make other flavors "pop," including sweetness and breadiness. That explains why I was never able to make a good English-style ale with it. You might be able to make a good IPA with it, but definitely not one of the oaky, malty beers associated with Old Blighty.

This is one of the most vigorous yeast strains I've ever known. I like to think that somehow, the environment of the tower fermenter evolved a very hardy yeast. Certainly, the tower fermenter would have selected for yeast that just didn't quit. And that's how we got Whitbred B-- the creature from the tower.

Danstar Windsor

Danstar's dry "Windsor" yeast is supposed to be a true English-style ale yeast. The flavor is good, but... this yeast has a major genetic flaw. It cannot digest maltotriose, one of the complex sugars that appears in malt. Of course, the higher your mash temperature is, the more complex sugars you will have in your wort. The end result is that if you mashed high, you will end up with a stuck fermentation-- like I did.

So my advice to you is, if you want to use this yeast, mash as low as you possibly can. And actually, don't use this yeast. Just get a good liquid yeast if you want to make an English style ale.

Unlike Fermentis, Danstar only gives you 77 billion cells in their 11 gram packs. So you have to either make a lower-gravity beer, accept that you will be underpitching, or buy multiple packs. Of course, you could also create a starter, but if you're going to go to the trouble of doing that, why not just use liquid yeast instead?

White Labs WLP300

I guess everyone knows that this is a great Hefeweizen yeast. It is the classic Weihestephan yeast. I don't really have much to add to that, except to say that I have found that fermenting low is good with this yeast. You don't need to ferment hot to get banana flavor. Jamil Zainasheff suggests 62F as a fermentation temperature. I have gotten really good results at 64F as well.

If you are making a Hefeweizen, you owe it to yourself to use this strain (or some other classic Hefeweizen strain). Don't even think about using WB-06 or any other dry yeast for a Hefe.

White Labs WLP051

I didn't know about this strain until recently. I assumed that it was similar to the other American ale yeasts like Chico-- a fast, robust fermenter with a very neutral flavor profile. It's not.

WLP051 is the old BRY-97 Ballantine ale strain. Sometimes people call it the Anchor strain, since that brewery uses it.

It's a relatively slow fermenter. I had a fairly long lag time with this strain, and the primary fermentation took more days than usual to show signs of subsiding. It's also not very temperature tolerant. I've been told that it "more of less stops fermenting" below 65F-- a theory that I didn't want to put to the test.

So, with all that in mind, why would you use it? I think there are a few reasons. One is that it finishes a little bit sweeter than beers done with Chico, which is nice if you want some residual sweetness in your beer. Another is that it has a distinctive flavor-- a little more personality. I think commercial brewers might have once favored this strain because it's easy to "top crop." That rationale probably doesn't apply to most homebrewers, but it's still interesting to have a little piece of history.