Oftentimes winemakers desire a slightly sweeter product than their fermentations offer. Rather than trying to halt fermentation early, leaving an unknown amount of sugar in the wine,  it is a much more predictable and common practice to back sweeten the wines, adding sugar to the dry wine prior to bottling.

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Back Sweetening White vs. Red Wines

One of the benefits of making your own wine, is being able to create a wine tailored to your specific tastes. Traditional “rules” of dry reds can be forgotten as you create a wine designed for your palate. There are different steps to sweetening red and white wines to ensure success.

 

Red Wine

• Lysovin:
  • An anti-microbial to kill off any remaining MLF bacteria. Only targets gram-positive bacteria such as Lacto-bacillus (not Acetobacter).
  • Prevents unfavorable interaction of sorbate and MLF bacteria (can cause geranium taint). Must be applied one week before sorbate and sweetening.
  • Use 1.5g/gal hydrated in 10 times its weight in water. Allow to sit for 45 mins.
  • Do not stir too aggressively to avoid foaming. Stir into wine gently but thoroughly.
  • To calculate 10 times a product’s weight in water:
    • Take amount in grams (Y) and multiply times ten (Y x 10=Z)
    • Then take Z (in grams) and use an online calculator to convert into pounds.
    • Then take Z in lbs and divide by the weight of one gallon of water (Z/8.2 =A) A will be the amount of water needed to hydrate the product.
  • Sorbate:
    • Potassium Sorbate will help prevent yeast from reproducing and refermenting the newly introduced back sweetening sugar.
    • Make sure wine has been thoroughly racked and clarified before applying sorbate.
    • Use 1gram/gallon and dissolve in warm water.
  • Sulfite:
    • It is important to ensure that your sulfite level is up to the suggested ppm for that varietal, contingent on that wine’s pH value.
    • Use the sulfite calculator on Winemaker Magazine’s website to determine the correct sulfite concentration contingent upon your wine’s pH.
  • Fructose:
    • Fructose is the primary sugar found in fruits such as grapes, that is the best for back sweetening to provide a natural sweetness to the finished wine.
    • Bench trials should be conducted to discern the level of sweetness preferred by the winemaker.
    • Please see the attached sheet for back sweetening bench trial protocols. Once a level has been determined, use the following equation to determine the amount of fructose to be added.
      • Amount of gallons x 8.2lbs/gallon = X (weight of wine)
      • Use X multiplied by the percentage of residual sugar desired will yield the amount of fructose needed.
        • Ex: 100 gallons x 8.2lbs/gal = 820lbs x 2% RS (.02)=16.4lbs of fructose needed.
      • Dissolve the sugar in as little hot water as possible. Mix into the wine via vigorous stirring or during a pump over.

White Wine

• Sorbate:
  • Potassium Sorbate will help prevent yeast from reproducing and refermenting the newly introduced back sweetening sugar.
  • Make sure wine has been thoroughly racked and clarified before applying sorbate.
  • Use 1gram/gallon and dissolve in warm water.
• Sulfite:
  • It is important to ensure that your sulfite level is up to the suggested ppm for that varietal, contingent on that wine’s pH value.
  • Use the sulfite calculator on Winemaker Magazine’s website to determine the correct sulfite concentration contingent upon your wine’s pH.
• Fructose:
  • Fructose is the primary sugar found in fruits such as grapes that is the best for back sweetening to provide a natural sweetness to the finished wine.
  • Bench trials should be conducted to discern the level of sweetness preferred by the winemaker.
  • Please see the attached sheet for back sweetening bench trial protocols. Once a level has been determined, use the following equation to determine the amount of fructose to be added.
  • Amount of gallons x 8.2lbs/gallon = X (weight of wine), Use X multiplied by the percentage of residual sugar desired will yield the amount of fructose needed.
    • Ex: 100 gallons x 8.2lbs/gal = 820lbs x 2% RS (.02)=16.4lbs of fructose needed.
  • Dissolve the sugar in as little hot water as possible. Mix into the wine via vigorous stirring or during a pump over.

 

Bench Trials for Back Sweetening

• Preparation of solution for bench trials:
  • Dissolve 40gm of Fructose into distilled water so final volume is 200ml
  • 100ml of solution contains 20gm Fructose which will raise RS of a gallon of wine by 1%

 

Bench testing:

• 50ml sample:
  • 13ml = 0.1%
  • 65 ml = 0.5%
  • 3ml = 1.0%
• 100ml sample:
  • 26ml = 0.1%
  • 3 ml = 0.5%
  • 6ml = 1.0%
• 375ml sample:
  • 0ml = 0.1%
  • 0 ml = 0.5%
  • 0ml = 1.0%
• 750ml sample:
  • 0ml = 0.1%
  • 0 ml = 0.5%
  • 0ml = 1.0%