winemaking calculations - purdue university
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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
Questions
Thank You!
HANDOUTS
Free SO2 and pH chart
Unit conversions/rules of thumb
Typed example calculations