« on: November 11, 2014, 07:41:13 AM »
To follow up on klickitat jim and majorvices, I would add some caution and clarify that a "stable" gravity reading means the yeast in its current state, regarding time, temperature, nutrients remaining, etc, is "done" fermenting but it does not mean that all the fermentable sugars are gone. It is important that if you are bottling that the yeast reaches terminal gravity. The kit instructions state that expected final gravity is somewhere between 1.016 and 1.020. If your beer never gets to that point and still reads a stable but slightly higher than recommended gravity, then you'll need to consider a few options:
1) rack to secondary - this helps rouse the yeast back into suspension, can add a bit of oxygen, and awaken the yeast to finish fermenting. However, you are reducing the amount of yeast and asking it to continue to ferment sugars when its already "tired or done". This may take some extended time to finish if you do nothing else. I'm not sure why most kit instructions recommend this step because I think for some beers this can be a crucial mistake. Residual sugars either make sweet beer or can cause much higher carbonation levels than expected or even create bottle bombs/gushers.
2) move your fermenter to a warmer place and/or rouse your fermenter. Rousing is simply stirring up the yeast sediment. For some english yeasts, this can be helpful to ensure they ferment out those last remaining sugars. An increase in temperature can also increase yeast activity. A ramp up in temperature at this stage is okay but a ramp down in temperature may stop fermentation. Some yeasts can be sensitive to even a couple degrees change and drop out of solution. Again, for me, this is most common with english strains.
3) use more "advanced" methods to help a stuck fermentation such as adding actively fermenting yeast to help ferment out those remaining sugars your first yeast could not finish
For your next batch consider reading up on rehydrating dry yeast, aeration, and temperature control.
Best of luck and no question asked is a stupid one!