Expert: Spencer W Thomas - 4/22/2007

Question
Hi,

Im brewing an Amber ale from a True Brew kit and my air lock did not begin bubbling until about Day 5. Even then, not much, very slow. It's now day 7 and still going, pretty slow. Obviously I'll wait until it stops before I bottle it, but I'm just curious--is something surely wrong? Is there anything I should do? The beginning gravity was exactly what the package indicated it should be.

Thanks,
Robby

Answer
Such a slow start indicates weak yeast.  Why?  

It might have been old -- do you know how long it might have been sitting at the retailer or in your home before you used it?  

It might not have been rehydrated before you pitched it. I note that the instructions for the kit (at least the online instructions) do not recommend rehydration.  Dried yeast will work better if you do this step.  It's quite simple.  You get a small bowl or measuring cup and put into it 1/4 cup of water at approximately 95-105F (if you don't have a thermometer, this temperature will feel warm-hot.  105 is the temperature at which many hot tubs are set, for example.)  You then sprinkle the yeast onto the water and let it dissolve for 5 minutes before pitching it into the wort.  

howtobrew.com has more detailed instructions for rehydration including a "proofing" step that helps insure that the yeast is ready to actively ferment your wort.  Some yeast manufacturers recommend against "proofing," though.  See http://howtobrew.com/section1/chapter6-5.html for the details.

Or, if you did rehydrate, your water might have been too hot and it killed the yeast.

Finally, your fermentation temperature may be too low.  If it's in the upper 60s, you're probably ok on this, but if it's lower than that, the yeast may not be working to its full potential.

It's possible that the slow start let some wild yeast or bacteria have their way with your beer.  Don't worry about this now, and it won't make your beer unsafe to drink, but it may cause some off (bad) flavors to develop.  Taste the beer at bottling.  If it's not horrible (it still won't taste quite right, because the job's not done yet), go ahead and bottle.  Some seemingly "off" beer becomes quite drinkable after it's been bottled, primed, and rested. If it tastes like you're licking a band-aid, or if it's horribly sour, or smells like cooked cabbage, then you might have to write off the batch as a learning experience.  Sad, but true.  

=Spencer