Transcript fermentation

FERMENTATION
By Jeff Louella
Why Understand
Fermentation?
Understanding the science
behind fermentation can
greatly affect the quality
of beer made.
There are some great products
on the market to help home
brewers excel.
Brewers make wort, Yeast
make beer. So be nice to your yeast.
Agenda
Designing a Beer’s Fermentability
Yeast Nutrition
Yeast Pitching
Controlling Fermentation
Fermentation Phases
Designing a Beer’s
Fermentability
Dry vs Sweet
Fermentability - Dry
All-Grain Mashing
Mash at a lower temperature
range. Many dry beers mash
between 148° - 151°
Use fermentable adjuncts
Sugar, Honey, Maple & Rice
Syrup, and Most Fruit will
ferment out dry
Fermentability - Sweet
All-Grain Mashing
Mash at a higher temperature range. Many full
mouth feel and sweeter beers mash between 154° 160°
Extract Brewing
Liquid Malt Extract tends to have an average
fermentability. Tough for big beers to ferment out
fully.
Adjuncts
Brews with a lot of adjuncts, such as roasted barley,
will not ferment out as much.
Yeast Nutrition
Carbohydrates
Nitrogen
Vitamins
Minerals
Zinc
Oxygen
Nutrition - Carbohydrates
Sugars in order of concentration
Maltose
Maltotriose
Glucose
Sucrose
Fructose
Nutrition - Nitrogen
Amino Acids
Amino acids collectively referred to as
"free amino nitrogen (FAN)," are the principal
nitrogen source in wort and are an
essential component of
yeast nutrition. It is the
amino acids that the yeast
cells use to synthesize
more amino acids and, in
turn, to synthesize proteins.
Peptides
Ammonium Salts
Nutrition - Vitamins
Biotin
Biotin deficiencies will result in
yeast with high death rates.
Panthotenic Acid
Thiamin
Inositol
Nutrition - Minerals
Phosphate
Phosphate is involved in energy conservation, is
necessary for rapid yeast growth, and
is part of many organic
compounds in the yeast cell.
Potassium
Potassium ions are necessary for the
uptake of phosphate.
Calcium
Magnesium
Sulfur
Nutrition - Zinc
The most important trace element is zinc, and at least
0.10 to 0.15 mg/l should be present in the wort.
Zinc assists in protein synthesis in yeast cells and
controls their nucleic acid and carbohydrate metabolism.
Fermentations are accelerated by adding zinc chloride
(0.2-0.3 mg/l) to the wort.
Nutrition - Products
Complete Nutrients
White Labs - Servomyces
Wyeast - Nutrient Blend
Nitrogen
Fermaid K
DAP
Nutrition - Oxygen
Oxygen is an essential nutrient for yeast growth.
Too low a level of dissolved oxygen can lead to
insufficient yeast growth and, therefore, sticking
fermentations.
Too much oxygen can lead to excessive production of
yeast.
Oxygenation Methods
Shaking Carboy
Aquarium Pump with Stone
Pure O2 with Stone
Yeast Pitching
Strain
Pitching Rates
Viability
Yeast Strain Specifications
Attenuation
Attenuation is the percentage of sugars that the yeast consume
during fermentation. If the fermentation went to 1.000 gravity,
that would be 100% attenuation. Understanding the different
attenuation ranges of each strain will help determine the
terminal gravity of the beer.
Ex. 1.050 OG to 1.012 FG = 75% Attenuation
Flocculation
Flocculation refers to the clumping of yeast cells at the end of
fermentation. Strains are separated into three main degrees of
flocculation- High, Medium, and Low. An example of a highly
flocculent strain would be an English Ale yeast, which will settle
at the bottom of the fermentation tank. An example of a low
flocculent strain would be a Hefeweizen yeast.
Pitching Rates
1 million cells of viable yeast, for every milliliter of wort,
for every degree plato.
1.050 OG - 5 Gallons Wort - 91% Viability
175 Billion Cells - 1.9 Vials or Smack Packs
1.080 OG - 5 Gallons Wort - 91% Viability
273 Billion Cells - 3 Vials or Smack Packs
Pitching Rate Calculator
www.mrmalty.com/calc/calc.html
Controlling Fermentation
Fermentation temperature control is one of the most
important thing you can do that will make the most
dramatic improvements in your beer.
High Esters, Fruitiness, and Fusel Alcohols (too
warm)
Incomplete Fermentation (too cold or temp drop)
Too Low Esters for Style (too cold)
Controlling Fermentation
Ways to Control Temperature
Temperature Methods
Refrigerator or Freezer
Fermwrap or Brew Belt
Temperature Control Units
Analog and Digital Controller
Dual Stage Controller
Fermentation Phases
Aerobic / Lag
Fermentation
Stabilization
Secondary Fermentation?
True secondary fermentation happens when more
sugars are added.
What most home brewers consider secondary
fermentation is basically the Stabilization phase.
For most brews, there is no need to move beer into a
secondary vessel.
Questions?
Thank You!