FERMENTATION
May 2014
FERMENTATION DEFINED
 Fermentation is the process in which
microorganisms convert organic compounds into a
simpler compounds.
 These organisms are typically yeast and bacteria
which ferment sugar thus creating beer, wine,
bread, kimchi, yogurt and other foods.
 The by-products of beer/wort fermentation are
carbon dioxide, alcohol and various flavor
compounds.
CHOOSING YOUR YEAST
What Kind of beer do you want to
make?
 Lager Yeast: (Saccharomyces pastorianus) Bottom fermenting,
slower fermentation at a temperature low enough that the yeast
cells can sink. Typically 45-55*F
 Ale Yeast: (Saccharomyces cerevisiae) Top fermenting, more
aggressive fermentation at a temperature high enough to carry the
yeast cells to the top of the fermenting liquid. Typically 60 -72*F
Try experimenting with different yeasts and fermentation
temperatures. Some yeasts will accentuate or mute malt and hop
character.
OPTIMIZING FERMENTATION
Having enough yeast: Doing a proper starter
for the volume/gravity of the beer you are
making.
Nutrients: Having enough yeast nutrients and
oxygen necessary for healthy fermentation.
Proper temperature control: Every yeast has a
sweet spot where they function best.
www.whitelabs.com and www.wyeast.com
FERMENTATION CONTAINERS
Glass Carboys
 Clarity allows you to gauge the activity of the
fermentation.
 Two sizes commonly available, a 6 1/2 gallon and 5
gallon
 Because they are clear, carboys must be shielded from
light
Food grade plastic buckets
 Less expensive than glass and safer to handle.
 Option of having spigots, which makes siphoning
unnecessary
 Spigots allow for easier bottling.
 Easier to add fruit and other adjuncts
.
T YPICAL HOMEBREW FERMENTERS
Buckets: $15
Glass Carboys: $30-40
AIRLOCK VS. BLOW-OFF TUBE VS.
FOIL
 Airlock is appropriate when there is adequate amount of head
space .
 A blow-off hose is appropriate when fermentation is vigorous and
there is less headspace, allows foam and hop remnants to be
carried out of the fermenter.
 Tinfoil can be used over carboy top
WHERE TO FERMENT?
 A place with a stable temperature within the appropriate
temperature range for the yeast being used. Ales 60 -72*F, Lagers
45-55*F
 Closets, basements, or a spare bathroom. Fermentation chamber
or refrigerator.
 Shield from direct sunlight for two reasons. sunlight will cause a
photochemical reaction with the hop compounds and skunk your
beer.
PRIMARY FERMENTATION
 Active fermentation should start within 12 o 24
hours.
 The three important factors for a successful
fermentation are 1) pitching enough yeast, 2) good
wort nutrients, and 3) maintaining a consistent
temperature in the correct range.
 It is not uncommon for an ale's primary
fermentation to be done 2-3 days. Lagers take
longer because of the cooler temperatures, 7 -21
days.
SECONDARY FERMENTATION
 Single stage: No transfer to secondary, wait 10 -14 days to
condition the beer and allow clearing, then proceed to packaging.
 Two stage fermentation: Longer conditioning time, gets beer off
majority of yeast, and may aid in clarification. A good place to
add fruit or other adjuncts.
TEMPERATURE AND FLAVOR
 Lager yeast produce less fruity esters than ale yeasts but can
produce more sulfur compounds during primary fermentation.
 Many first time lager brewers are astonished by the rotten egg
smell coming from their fermenters, sometimes letting it convince
them that the batch is infected and causing them to dump it. Don't
do it! Fortunately, these compounds continue to vent during the
conditioning (lagering) phase and the chemical precursors of
other odious compounds are gradually eaten up by the yeast. A
previously rank smelling beer that is properly lagered will be
sulfur-free and delicious at bottling
TEMPERATURE CONTROL TOOLS
Brew Belt/heater: $30
Thermostat $57
HIGH TECH HOME FERMENTATION
LOW TECH HOME FERMENTATION