winemaking calculations - purdue university

Winemaking CalculationsAmanda StewartPurdue Wine Grape Team29 April 2011Spring WorkshopBuck Creek Winery

SO2 is on Your SideWhy?Microbial StabilityInhibition of browning enzymesBinding of acetaldehydeAntioxidant

Commercial average 74 mg/L

C. Butzke 2006, Wine Quality Control Basics

Free SO2 and pH

pH Free SO2 REQUIRED

Free SO2 and pH

Example Calculation

Assume 1000 gal of winepH = 3.44No SO2 has been added yetPlan to bottle with residual sugar

How Much SO2?For pH = 3.44, we need:

Plus an extra 30 mg/L to cover losses

Addition:

35 mg/L Free SO2

35 mg/L + 30 mg/L = 65 mg/L Free SO2

How many grams to put in the tank?

UNITS!1 gallon = 3.785 Liters 1 gal/3.785 L = 1

1 g = 1000 mg 1 g/1000 mg = 1

How many grams? Convert F SO2 from mg/L to g/gal 65 mg/L*(3.785 L/1 gal)*(1 g/1000 mg) = 0.246 g/gal

Add as Potassium Metabisulfite, (KMB) Potassium Metabisulfite is only 58% SO2 Conversion factor from SO2 to KMB = 1.7 0.246 g/gal * 1.7 = 0.418 g/gal KMB

We have 1000 gal of wine, so: 0.418 g KMB/gal * 1000 gal =

418 g Potassium Metabisulfite

How to Protect the Wine?Assume 1000 gal of winepH = 3.44No SO2 added yetPlan to bottle with RS

Potassium Sorbate Addition

Potassium Sorbate

Sorbate Target 200 mg/L sorbate

How many grams to add to our tank?

200 mg/L *(3.785 L/1 gal)*(1 g/1000 mg) = 0.76 g/gal sorbate

Potassium Sorbate is only 74% sorbic acid

Conversion factor: 1.35

(0.76 g/gal)*1.35 = 1 g/gal

1 g/gal * 1000 gal = 1000 g potassium sorbate

Potassium Sorbate

Gut checkPotassium metabisulfite:Adding 423 g to 1000 gal wine

Potassium sorbate:Adding 1000 g to 1000 gal wine

Does this seem right?

Impact on Cold Stability!Adding more Potassium

Potassium Sorbate

Weight! For bench trials, need to weigh ± 0.01g0 – 500g capacity

For additions of SO2 and Sorbate, need to weigh ± 1 g0 – 2 kg capacity

Gut Check

Material 1 cup weighs?PotassiumMetabisulfite(Powder)

341 g

Potassium Sorbate

103 g

Sugar, granular 200 g

BlendingSensory Impact Requires Blending

Trials

Chemical Composition CalculationAcidAlcohol

Blending 2 Wines - Alcohol

Pearson’s Square

a

b m-a

b-mm

11%

Blending to target 12% alcoholWine “a” has 11% alcoholWine “b” has 14% alcohol

14%

12%14-12=2 2 Parts A

12-11=1 1 Part B

3 Parts Total

Blending 2 Wines - TA

Target 6.5 g/L

a

b m-a

b-mm

Wine “a” has 7.1 g/L TAWine “b” has 8.9 g/L TA

Blending 2 Wines

Target TA 6.5 g/L

a

b m-a

b-mm

Wine “a” has 5.4 g/L TAWine “b” has 8.9 g/L TA

5.4

8.9 1.1 Parts B

2.4 Parts A6.5

3.5 Parts Total

Blending for TA, cont’d Need to use 2.4 Parts A, 1.1 Part B

Total Volume Desired = 250 gal

Determine proportions 3.5 total parts 2.4 parts A/3.5 total parts = 0.686 A 1.1 part B/3.5 total parts = 0.314 B The whole is the sum of its parts A+B = 1 0.686 + 0.314 = 1

How much of Wine A and Wine B to make 250 gal blend?

A: 250 gal*0.686 = 171.5 gallons of wine A B: 250 gal*0.314 = 78.5 gallons of wine B

Sugar Additions Large sugar additions increase wine/juice volume

500 gal of juice at 18 Brix, desired to have 22 Brix

Need to add ~4% sugar, or 40 g/L

40 g/L * (3.785 L/1 gal) = 151.4 g/gal

151.4 g/gal * 500 gal = 75,700 g = 75.7 kg

75.7 kg * (1 lb/0.454 kg) = 167 lb sugar (!)

Sugar Additions How much additional juice volume will result?

167 lb sugar = 75.7 kg sugarDensity of CRYSTALLINE SUGAR ≈ 0.85 kg/LDensity of DISSOLVED SUGAR ≈ 1.7 kg/L

75.7 L crystalline sugar/1.7 kg/L = 45 L dissolved sugar

Final juice volume is increased: 500 gal + 45 L/(1 gal/3.785 L) = 512 gal

SummaryYes, online calculators are available

Proficiency in winemaking calculations Reduce chance of mistakesMake additions to juice/wine with confidence

Online Calculator

http://vinoenology.com/

Questions

Thank You!

HANDOUTS

Free SO2 and pH chart

Unit conversions/rules of thumb

Typed example calculations