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Problem Fermentation and Yeast Hulls

Premature cessation of an alcoholic fermentation, commonly known as a stuck fermentation, is a serious winemaking problem. Restarting a stuck fermentation is often difficult and time consuming, but more importantly, it creates a favorable condition for the growth and activity of spoilage microorganisms. There are several factors that are responsible for fermentation problems. Read more about Problem Fermentation and Yeast Hulls

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Wine Aging

Wine aging refers to a group of reactions that tend to improve the taste and flavor of a wine over time. The term wine 'maturation' refers to changes in wine after fermentation and before bottling. During this period, the wine is subjected to various treatments, such as malolactic fermentation, clarification, stabilization, and bulk storage. Read more about Wine Aging

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Racking

When a fermentation ceases, the suspended particles settle rapidly and form a sediment. The sediment, referred to as lees, usually consists of macerated grape tissue, dead yeast cells and yeast autolysis products. The young wine is separated from the lees by transferring the wine to another container, leaving the lees behind. This process is called racking.  Read more about Racking

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Racking Wines*

When a fermentation ceases, the suspended particles settle rapidly and form a sediment. The sediment, referred to as lees, usually consists of macerated grape tissue, dead yeast cells and yeast autolysis products. The young wine is separated from the lees by transferring the wine to another container, leaving the lees behind. This process is called racking.  Read more about Racking Wines*

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Some Issues in Malolactic Fermentation Acid Reduction and Flavor Modification*

Lactic acid bacteria (LAB) play an important role in winemaking. They are involved in malolactic fermentation (MLF), which is also called secondary fermentation. Malolactic fermentation causes acid reduction, flavor modification and also contributes to microbiological stability.  Read more about Some Issues in Malolactic Fermentation Acid Reduction and Flavor Modification*

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Determining Residual Sugar Using a Hydrometer*

Many winemakers use a brix hydrometer having a scale of +5.0 to -5.0 to estimate the residual sugar content and evaluate the completion of fermentation. Although this is not an accurate method to determine residual sugar content in a wine, it does serve as an indicator of the progress of the fermentation. A hydrometer reading combined with a clinitest reagent tablet test and an alcohol test can provide a better estimation of the residual sugar content in a wine as compared to any of the tests used individually. Read more about Determining Residual Sugar Using a Hydrometer*

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Ethyl Carbamate Content in Wines*

Ethyl carbamate is known for its carcinogenic effect on some laboratory animals; it has not been conclusively proven to be a carcinogen for human beings. Because of the suspicion that ethyl carbamate may pose a health risk, a considerable amount of research has been done. The studies have shown that ethyl carbamate is naturally present in many fermented food products including certain wines. The amount appears to be relatively high in fortified wines and brandies which involve heating in their production. Research has also shown that urea is a primary precursor of ethyl carbamate in certain wines. Urea is a by- product of arginine (naturally occurring amino acid in grapes) breakdown by the yeast.  Read more about Ethyl Carbamate Content in Wines*

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