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potassium sorbate

The Winemaker’s Think Tank: Vol 17 – Should I Add Sugar?

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What’s the Winemaker’s Think Tank?

Every Thursday we will post about a few frequently asked questions that our winemaker has answered. If you have a winemaking question you would like to have answered, please email us at support@juicegrape.com and we will try to get into next week’s post. Cheers! :)

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Do I add sugar?

Adding sugar can fall into two categories. If sugar is added prior to fermentation, it is called chapitalization and will increase the Brix (sugar level) of the must, resulting in a higher alcohol by volume wine. The yeast will process this sugar in addition to the grape sugars and will turn it into alcohol. Chapitalization is an important step for under ripe grapes, lacking in sugar.

Another form of sugar addition to wine is post-fermentation. This must be done with much care as to not restart fermentation. Adding the sugar after fermentation may reactivate yeast by offering them another food source and cause them to ferment that sugar as well. This can be prevented by adding sulfites to at least 50ppm to kill off the yeast. Adding sugar after sulfites will effectively back sweeten the wine, giving residual sugar and a sweet flavor to the wine. The winemaker can also add potassium sorbate to the wine, provided that the wine has not gone through malo-lactic fermentation. Potassium sorbate cannot be added to a wine that has undergone MLF as it will result in an off aroma of geranium taint. Potassium sorbate is strongly suggested for white wines that the winemaker would like to add residual sugar to. The sorbate will encapsulate any yeast particles, prohibiting them from metabolizing the sugar that was added for sweetening.

We hope this information helps with your winemaking. If you have any follow up questions or winemaking questions in general, please email us at support@juicegrape.com.

The Winemaker’s Think Tank: Vol 5 – Is Malocatic necessary in White Wines if it has not been inoculated?

Wine expert testing wine silhouette image

What’s the Winemaker’s Think Tank? 

Every Thursday we will post about a few frequently asked questions that our winemaker has answered. If you have a winemaking question you would like to have answered, please email us at support@juicegrape.com and we will try to get into next week’s post. Cheers! :)

Is Malocatic necessary in White Wines if it has not been inoculated?

When considering the stability of a white wine in preparation for bottling, sugar and microbial stability are of great importance. After fermentation, if MLF is not purposefully inoculated by the winemaker, the addition of Lysozyme may be considered as to retard any naturally present MLF bacteria from beginning to ferment. If the level of SO2 is kept up to is suggested level (contingent upon pH), the Lysozyme may not be needed as the SO2 will prevent the bacteria from fermenting. If the winemaker is trying to use a low amount of sulfites in their wine, I would suggest the use of Lysozyme to inhibit any bacterial growth.

Equally as important, is the use of sterile filtration. If the wine is processed through a sterile filter (.45µ), bacterial and yeast cells should be eliminated. This will physically prevent the bacterial spoilage of the wine. If the winemaker chooses to back sweeten the wine, this filtration will also help prevent any refermentation within the bottle. When it comes to back sweetening, I also always recommend chemical as well as physical sterilization of the wine to prevent fermentation and off aromas to develop within the bottle. Potassium sorbate may be used on any wine that has not gone through malolactic fermentation. If it is used on a wine that has undergone MLF, remaining MLF bacteria can begin to metabolize the sorbate, resulting in a strong geranium odor. In my experience, I typically add sorbate and sterile filter the wine, then bottle, without the addition of Lysozyme. I am meticulous about the level of SO2 remaining above the suggested amount , and I typically add an additional 10ppm before bottling to ensure prolonged sterility within the bottle.

While you certainly can conduct a chromatography test upon the wines to detect the presence of acid, both malic and lactic exist naturally within the grape, so the chromatography test will not be especially helpful when looking at a wine that has not gone through MLF. As long as you keep a vigilant watch upon your sulfur dioxide levels and pH, and use sorbate when sweetening, you should be fine.

We hope this information helps with your winemaking. If you have any follow up questions or winemaking questions in general, please email us at support@juicegrape.com.