Stupid Stuff for Smart Brewers - Part 2 - Fermentation

In the second part of Stupid Stuff for Smart Brewers I am going to sum up all of the fermentation tips, tricks, and information from "Stupid Stuff All Brewers Should Know But Often Don't" by Jamie Martin.

Here is the "F-you Bill, I am just going to read the actual article" link. 

Since we now know that it is incredibly important to keep all of your brewery equipment clean and sanitized to keep all the baddies out, we will go over some common fermentation problems that can happen in even the cleanest brewing equipment.

Fermentation Doesn't Start

If your fermentation doesn't start here are a few of the most common easily fixable reasons why:

• Oxygen Level - When in a brewing situation yeast goes through two different stages. The stage that gets the most attention is anaerobic glycolysis to turn sugars into CO2 and alcohol, but to be able to get to that stage the yeast needs to use oxygen in reproduction. If there isn't enough oxygen present in the wort, then the yeast won't be able to reach a high enough cell count to ferment at maximum efficiency. The simple solution for this is to add oxygen to your wort. Depending on the size of your operation, you can accomplish this by bubbling oxygen through the bottom of your tank, or taking the lid off and shaking your carboy.
• Wort Temperature - When you pitch your yeast the temperature is very important. The temperature needs to be within a range that is comfortable for the yeast. If your wort is too hot, then there is a chance that you could cook your yeast. If this happens, then all you have to do is wait for the wort to get to a good temperature, and pitch new yeast. If the wort is too cold, then heating the wort to a good temperature to activate the yeast already in the wort, and no additional yeast needs to be pitched.
• Yeast - This is more of an issue if you reuse yeast. There are many factors that could make your saved yeast unusable. Yeast doesn't like being stored under pressure, with too much dead yeast, and in fluctuating temperatures. If any of these conditions were present then there is a possibility that your yeast is either dead or very unhealthy. If you think this is the issue, then move the wort off of the bad yeast, and pitch new yeast. If you leave the bad yeast in the wort then there will be a chance that it will create off flavors, or compromise the health of your new yeast due to yeast autolysis.
• Time - If you believe that your fermentation didn't start, you might just need to wait. Some yeast works faster than others, so waiting an extra day before hitting the panic button might be a good idea. 

Stuck Fermentation

If your fermentation stops before the target specific gravity here are a few common reasons why:

• Malt - For any number of reasons you might not have gotten as much extract as you were expecting out of the malt during the mashing process. There is nothing that you would be able to do to alleviate this situation, and it would leave you with a sweeter beer with a lower alcohol content than you were expecting.
• Yeast -  Your fermentation might not be stuck. Some strains of yeast work very slowly in high alcohol environments at the end of fermentation. If you didn't reach the gravity that you were hoping for, and it appears that fermentation has stopped, then there is a chance that this might be your issue. Yeast can still be working at this slower rate for up to two more weeks, and this could have a large impact on your final specific gravity.