Bottle conditioning

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Bottle Conditioning: Yeast Refermentation Neva Parker Head of Laboratory Operations White Labs, Inc.

Transcript of Bottle conditioning

Page 1: Bottle conditioning

Bottle Conditioning:Yeast Refermentation

Neva ParkerHead of Laboratory Operations

White Labs, Inc.

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Outline

• Basics of bottle-conditioning– Overview of the biology – Methods– Advantages & Challenges

• The Refermentation– Yeast strain selection– Yeast quality & yeast health– Dosing rate

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Basics of Bottle Conditioning

Yeast MetabolismHappens during fermentation & refermentation

EtOH & CO2

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Basics of Bottle Conditioning

Fermented Beer + Sugar + Yeast (+ 2-3 weeks)

= Carbonated Beer

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Basics of Bottle Conditioning

A quick note on CO2:

Dissolves in beer – more dissolves at lower temps

Measured as Volumes of CO2 - each Volume is basically ~2 g/L

Most labs use a pressure gauge & conversion chart to measure Volumes

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Basics of Bottle Conditioning

Methods:

1. Krausening2. Partial forced-carbonation & bottle-condition3. Use clear/filtered beer, add back sugar, add new

yeast

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Why Bottle-Condition?

Tradition

Special Products/Marketing

Stable Shelf-Life

Improved Sensory

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Challenges to Bottle-Conditioning

Consistent carbonationEnvironmental (for yeast) – alcohol & pH levelsCan be more difficult & time-consumingTemperature to hold packagesTime & cost of holding inventoryPotential flavor impacts from second fermentationAppearance of sediment to consumers

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The Refermentation: What you need to know

Yeast Strain Selection

Dry vs. Liquid – is there a difference? - In laboratory trials – performance is similar- Possible flavor impact, but its strain-dependant

Alcohol & pH tolerant yeast- California Ale Yeast or equivalent- Some neutral wine strains

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The Refermentation: What you need to know

Yeast Strain SelectionFlocculation properties

- Settles well at the end of refermentation

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The Refermentation: What you need to know

Yeast Strain SelectionFlocculation properties

- Sticks to bottom of package - Produces a fine sediment

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The Refermentation: What you need to know

Yeast Strain SelectionSensory Contribution

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The Refermentation: What you need to know

Yeast Strain SelectionSensory Contribution

Flavors:- Generally, not perceivable if using a neutral yeast

strain- Some esters & fusels will be produced as part of

the fermentation- Will help prevent oxidation and consume any

left-over diacetyl

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The Refermentation: What you need to know

Yeast Strain SelectionSensory Contribution

Mouthfeel- Bottle-conditioned beer has been reported to

have a fluffier, longer-lasting head- By trained taste panel, described as being

smoother carbonation & more efferevescent

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The Refermentation: What you need to know

Yeast Strain SelectionUsing Brettanomyces

- Produces CO2 as brewers yeast, can be dosed similarly

- Contributes flavor compounds but takes longer to develop

- Can metabolize larger sugars, so that should be taken into account

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The Refermentation: What you need to know

Yeast QualityShould be fresh yeast (early generation, 3rd or less)

Poor viability = Poor CO2 productionCan also lead to autolysis & cell components leaking

into beer = yuck Contamination can lead to off-flavors in final package

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The Refermentation: What you need to know

Yeast Dosing Rate

Typical beers range from 2.5-3.5 Volumes CO2

Recommended:500,000 cells/ml beer – 1 million cells/ml beer

SO….you need to do a CELL COUNT

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The Refermentation: What you need to know

Yeast Dosing RateA quick refresher on cell counting:

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The Refermentation: What you need to know

Yeast Dosing RateA quick refresher on cell counting:

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The Refermentation: What you need to know

Yeast Dosing RateA quick refresher on cell counting:

• Yeast cells are easily seen at 40X power.

• You may also notice trub in your viewing field that may stain.

• Yeast buds emerging from the mother cell are counted as separate cells if the bud is at least one-half the size of the mother.

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The Refermentation: What you need to know

Yeast Dosing RateA quick refresher on cell counting:

• Dead cells will stain dark blue• Cells that are clear or pale

blue in color are considered alive.

• Some budding cells will stain dark blue, but they are not dead! Buds are busy with growing metabolism and not extruding the dye.

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The Refermentation: What you need to know

Yeast Dosing RateA quick refresher on cell counting:Calculate your Cell Count:

Take the total # of cells you counted in the 25 squares 1,510Determine your dilution factor of your sample. 1:100 Volume in Hemacytometer chamber is 1/10,000 ml

Yeast cells/ml= Total cells in 25 squares x dilution factor x volume in hemacytometer chamber (1x10^4)

Example:1,510 x 100 x (1 x104) = 1.51 x109 or 1.51 billion cells/ml

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The Refermentation: What you need to know

Yeast Dosing RateA quick refresher on cell counting:

Calculate your viability:

# of live cells ÷ total number of cells x 100% = viability %

Example: 7 dead cells total 1475 ÷ 1510 x 100% = 97.7% viable

You’ll want yeast to be as viable as possible – nothing below 90%

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The Refermentation: What you need to know

Yeast Dosing Rate

Calculation:{(1x10^6 * 119,333)/2.41 x 10⁹} / 1000

= Liters of yeast slurry

Volume of wort in milliliters

Cell count of slurry (cells/ml)

Conversion factor for Liters

Desired pitch rate (cells/ml)

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The Refermentation: What you need to know

Sugar – what kind and how much?

- Malt or DME- Corn sugar or table sugar- Various other sugars such as cane sugar,

honey, corn syrup, Belgian Candy sugar

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The Refermentation: What you need to know

Sugar – what kind and how much?

- Typically 0.5lb-0.75lb to achieve 2.5-3.0 Volumes of CO2

- Bottle-Conditioning worksheet by John Mallet of Bell’s Brewing

Remember: the type and amount of sugar can influence the yeast fermentation

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Successful Conditioning

Proper sugar additionProper yeast strainGood yeast quality and yeast healthProper dosing rateImplementation of a good quality control program

for bottled product

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THANK YOU!

Questions?

Neva [email protected]