Reduced sulfur compounds (those formed in the absence of oxygen) are a perennial problem in winemaking because they usually smell very foul (rubber, swamp, cabbage, garlic). They also reduce a wines mouth feel and enhance bitterness.
This is the latest version (Oct 2014) of the Excel tool the Willem Wyngaards developed on the basis of the previous article. We call it a YAN calculator, but it is really a nitrogen addition calculator (and it also calculates yeast additions).
There is general agreement that white juice should be fermented at cool temperatures, taking several weeks to complete the process rather than the several days common with red must. Keeping white ferments cool is particularly applicable for the aromatic style. The cooler ferments can yield better varietal fruit flavor.
Lysozyme is the “silver bullet” necessary for preventing malolactic fermentations in aromatic white wines. This article discusses how to prepare and use Lysozyme.
If you have tasted a good Riesling or Gewürztraminer, you know what the light-bodied aromatic style of white wine is all about. Compared to an oaky Chardonnay, these aromatic wines: are higher in acid and lower in alcohol, use no oak, avoid malolactic fermentation (MLF), and usually have some residual sugar to balance the higher acid.
Chardonnay, especially the oaky, buttery kind, is the classic example of a full-bodied, wooded style white wine. Making it is more like making a red wine than an aromatic white wine, such as Gewürztraminer.
Making White WinesView Post
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Yeast requires nitrogen for fermentation. If there is not enough, yeast cells are stressed and produce excess H2S—something that gives fermentations an off-odor. If you want to avoid problems, you must be prepared by adding nitrogen to fermentations.
You don’t need to follow these directions to get a ferment to work, but you will be more likely to get a ferment that produces better wine flavors and minimal H2S if your give the yeast a proper start in life.