Expert: Keith Patton - 10/2/2007

Question
Hi Keith,
        This is the first time its ever happened to me. I made a wort for a pale ale, and thought of adding a little clove essence for flavor. I then pitched the yeast, but nothing happened. I pitched some yeast again yesterday and nothing is happening. Ive never had a batch not ferment before, could it be because of the clove essence(boiled cloves in water for a minute and added that liquid to the wort)? If so what can I do to remedy it? There is no sign of fermentation- no crud ring, no CO2 escaping through the air lock. Please help me as I do not want to lose all the time and effort I put into making my wort.
Thanks,
Sai

Answer
It sounds like a stuck fermentation.  You probably need to aerate the wort.  Plug the carboy and shake it or with it sitting with one corner on the counter, rock it back and forth.  Yeast is aerobic when it starts to ferment.  It needs the oxygen that is dissolved in the wort.  Unfortunately, boiling drives off the oxygen.  So you need to aerate the wort before pitching the yeast.  It can be done as described by shaking.  I use a device i made. I took a short section of 3/8 copper tube, platic will do to. near one end I drilled two sets of holes completely through both sides so that they formed a cross. I place this in the end of my siphon tube that goes into the carboy I am filling.  What happens is bernulli's principle. The liquid passing through the tube and my device pulls in air through the holes and aerates the wort as I siphon it from the pot into the carboy.  You will see the difference in the form of a nice foamy head in the wort as it collects in the carboy.

Back to your problem.  Try shaking it for 5 minutes or so.  Take a break if you need to.  Have some new yeast ready to pitch.  Don't just pitch the yeast from the container, or slap pack.  Make a starter first. Boil about a pint to a quart of unhopped wort made from extract syrup or dry extract.  Gravity should be on the light side. Cool pitch your yeast and when the kreusen rises and the yeast has kicked off well in the starter, pitch it in your stuck wort.  Another trick is use yeast nutrient.  Add it to the carboy when you are siphoning in your wort and it will dissolve during agitation.  This helps the yeast get a healthy start.

If you are using dry yeast, a starter is a must.  You can make a starter a day or two before you brew and it should be going strong when you need it.  It takes too long for dry yeast to hydrate and get going when pitched directly into the wort.

Keith