Dave, Desiree, Beer & Wine

As an owner of a homebrew shop we get a lot of questions about brewing beer and wine.  Over the last five years I have seen a trend of very common questions that are asked by new brewers.  My philosophy is that no question is stupid.  Everyone has to start somewhere and if time can be saved by asking me instead of trying to look it up, then I’m happy to answer.

So here is question numero uno that we at High Gravity answer on a frequent basis:

“My airlock has stopped bubbling.  Did I ruin it?”

Now if you have been brewing for a long time this question can seem rather silly but new brewers tend to jump in head first and read/ask questions later.  Most starter kits come with a small book that explains the brewing process but who wants to read that boring stuff when there’s beer to be made! The learning comes as we go, right?

Well, the first thing new brewers tend to learn is that the airlock is supposed to stop bubbling.  When beer first starts to ferment, there is a lot of sugar for the yeast to munch on.  The byproduct of fermentation is co2 and alcohol. As the co2 builds up it, pressure builds in the primary and needs to escape.  The result is the feverous activity of the airlock.  As the sugars are reduced the yeast slows down until there isn’t any food left to eat.  When this happens co2 is no longer being produced and the airlock stops showing activity.  That is a very good thing.  It means your beer is ready for the next step!

Another variation to this question is, “When I first pitched my yeast the airlock was going crazy and after just 2-3 days it has stopped.  The last batch I made bubbled for a week. How do I get it to start bubbling again?”

The answer to this question is basically the same.  It has stopped bubbling because there is nothing left to ferment.  The fermentation process is affected by many variables.  Rapid fermentation that completes in just a few days is usually due to temperature.

Warmer temperatures create a more vigorous fermentation.  Many new brewers think this is great.  After all, the faster it ferments the sooner we get to drink it, right?  Not really.  Warmer fermentation temperatures create excessive ester (fruity) and phenol (clovey or medicinal) flavors that can detract from the beer you are making.  The optimum fermentation temperature for most ales is 65-70°.

Many guidelines suggest pitching the yeast when the wort (unfermented beer) is at or below 80° and the reasoning is that the beer will continue to cool and reach 70° or so within 24 hours.  However, when yeast is pitched in wort that is at or above 80°, the yeast will have already started to vigorously ferment and these esters will be present.  I recommend trying to get the wort as close to your target fermentation temperature as possible before you pitch your yeast.  This allows the yeast to acclimate properly and you will be rewarded with a better beer, even if it does take an extra week to finish…

Desiree Knott

desiree@highgravitybrew.com

http://www.highgravitybrew.com

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This entry was posted by Desiree Knott on Saturday, May 30th, 2009 at 2:22 pm and is filed under Homebrew Related Posts. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.