Is Extract Really THAT Unfermentable?

Posted on 06.26.08 7:56PM under Brewing, Extract

A few weeks ago, I made an extract brew for the first time in a while. I got an OG of 1.058, and BeerSmith told me that US-05 should produce a FG of 1.011. Normally I get more attenuation than that, and I would have expected like 1.009 or even lower. But this one stopped at 1.019. I thought I did something terribly wrong, and the yeast wasn’t fully viable.

At bottling time, I thought one of two things would happen. 1) The yeast was spent, and would not consume the priming sugar, resulting in flat beer. 2) The yeast was just sleeping, and would become invigorated by the mini fermentation of the priming sugar, and keep going, resulting in bottle bombs.

Neither happened. The beer’s perfectly carbonated as intended by my priming sugar dosage. Or as perfectly as I get. I even had some bottles that have been warm for an extra few weeks. I’ve been giving these ones away, and I suddenly got worried that they might be bottle bomb candidates, since most of the ones I’ve been drinking were put in the fridge after precisely two weeks of conditioning, and would be basically yeast-inactive at this point.

So I put one of the warm bottles in the fridge yesterday. Popping it today, it is not overcarbonated at all. It’s pretty much the same as the cold bottles. If anything, the flavor is a bit richer. Even the decline of hop flavor and aroma seems less severe in this bottle than in the ones that have been cold longer. Which is the opposite of what I would have thought. I guess that’s why those brewboard guys are always talking about long secondaries.

I’m forced to wonder: is extract really that unfermentable? Or do I just mash at way too low of a temperature normally? Maybe somewhere in the middle. Next time I’ll try mashing at like 154 instead of 152.

Read Comments

  1. Posted by E.S. Delia on 06.27.08 8:09 AM

    So it’s normal practice to refrigerate in order to halt the activities of the sugar-consuming yeast? I was worried that the bottle bomb happening might occur with the Belgian-style brown we’ve got bottle conditioning, but we did have it in a secondary for some time before bottling, so I guess we’re okay…

    The thing is, I’m wondering if that will hurt the beer over time; it’s still got a couple weeks left before it’s supposed to be ready for consumption. Since you noticed less decline of flavor in the warm ones than the cold ones, we could be on the right track with ours.

    Man, there’s a lot to think about when you’ve got your own production line going!

  2. Posted by Keith Brainard on 06.27.08 11:32 AM

    I would not count on cold temperatures to stop the yeast. They’ll eventually resume activity if they have more work to do. This happened to me in some beer I made at a Brew-On-Premise. They were stable for a while, but months later, the bottles were a lot more carbonated, almost to the point of gushing.

    Generally there’s a finite amount of sugars that the yeast strain you use will consume, so if it’s been in secondary for a while, the yeast should be done consuming, and just be working their conditioning/aging magic on the batch.

    I wonder how much of a gravity drop it takes to build enough pressure to create a bottle bomb?