Equipment Glossary Acknowledgements


Site Map
Introduction
Section 1
Brewing Your First Beer With Malt Extract
1 A Crash Course in Brewing
2 Brewing Preparations
3 Malt Extract and Beer Kits
4 Water for Extract Brewing
5 Hops
6 Yeast
7 Boiling and Cooling
8 Fermentation
9 Fermenting Your First Beer
10 What is Different for Brewing Lager Beer?
11 Priming and Bottling
Section 2
Brewing Your First Extract and Specialty Grain Beer
Section 3
Brewing Your First All-Grain Beer
Section 4
Formulating Recipes and Solutions

 

 

[an error occurred while processing this directive]

 

Chapter 8.1.3 - Temperature Factors

8.1.3 Temperature Factors

The third factor for a good fermentation is temperature. Yeast are greatly affected by temperature; too cold and they go dormant, too hot (more than 10F above the nominal range) and they indulge in an orgy of fermentation that often cannot be cleaned up by conditioning. High temperatures encourage the production of fusel alcohols - heavier alcohols that can have harsh solvent-like flavors. Many of these fusels esterify during secondary fermentation, but in large amounts these esters can dominate the beer's flavor. Excessively banana-tasting beers are one example of high esters due to high temperature fermentation.

High temperatures can also lead to excessive levels of diacetyl. A common mistake that homebrewers make is pitching the yeast when the wort has not been chilled enough, and is still relatively warm. If the wort is, e.g. 90¡F, when the yeast is pitched and slowly cools to room temperature during primary fermentation, more diacetyl will be produced in the early stages than the yeast can reabsorb during the secondary stage. Furthermore, primary fermentation is an exothermic process. The internal temperature of the fermentor can be as much as 10F above ambient conditions, just due to yeast activity. This is one good reason to keep the fermentor in the proper temperature range; so that with a normal vigorous fermentation, the beer turns out as intended, even if it was warmer than the surroundings.

Brewing in the summertime is a definite problem if you don't have a way to keep the fermentor cool. My friend Scott showed me a neat trick though, he would immerse (not completely) his fermentors in a spare bathtup during the summer. The water in the tub was slow to warm during the day even though temperatures would be in the 90's, and at night the water would be slow to cool, even when the temperature dropped to 45 F. In this way he was able to moderate his fermentation temperature between 60-70 F, and the beer turned out great. I have used this method myself with wash tubs and had great success.

Previous Page Next Page
Fermentation
8.0
Some Misconceptions
8.1
Factors for a Good Fermentation
8.1.1
Yeast Factors
8.1.2
Wort Factors
8.1.3
Temperature Factors
8.2
Re-defining Fermentation
8.2.1
Lagtime or Adaptation Phase
8.2.2
Primary or Attenuative Phase
8.2.3
Secondary or Conditioning Phase
8.3
Conditioning Processes
8.4
Using Secondary Fermentors
8.5
Secondary Fermentor vs. Bottle Conditioning
8.6
Summary
Real Beer Page

Buy the print edition
Appendix A - Using Hydrometers
Appendix B - Brewing Metallurgy
Appendix C - Chillers
Appendix D - Building a Mash/Lauter Tun
Appendix E - Metric Conversions
Appendix F - Recommended Reading

Search How To Brew:




All material copyright 1999, John Palmer