Hello there! I'm Dr. Vinifera, or "Vinny" for short. Ask me your toughest wine questions, from the technical aspects of winemaking to the fine points of etiquette. I hope you find my answers educational and even amusing. Want to see more of them? Check out my archive.
December 01, 2008:
Dear Dr. Vinny,
What is the term for the gap in the bottle of wine from the top to the neck—the empty space?
—Vinod P., India
Dear Vinod,
That space is called "ullage" (pronounced "UH-lij"). Ullage refers to the unfilled space in any container of liquid, whether it's the unfilled air space at the top of a bottle of wine or the space within a fuel tank in a liquid rocket. Ullage allows for the expansion of the liquid as temperature changes, just in case it needs it.
Normal ullage for a young wine is quite small; the liquid should come up into the neck of the bottle. If there is more ullage, the wine's quality may be compromised. An older wine may have more ullage and still be fine.
—Dr. Vinny
November 26, 2008:
Dear Dr. Vinny,
Can you tell me what wines should not be chilled? My husband wants to put every type of wine in the cooler.
—Mary Beth, Cincinnati
Dear Mary Beth,
When it comes to storing wines, all wines benefit from cool temperatures, which can slow down the aging process and protect wines from elements that might prematurely age them. So if your husband is storing all your wines in a wine cooler, that's a smart move.
When it comes to serving wine, sparkling wines will show their best when chilled, as will white, pink, and most dessert wines. Many folks serve their reds at room temperature, but depending on the temperature of the room, that might be too warm. Above all, let your own preferences be a guide.
—Dr. Vinny
November 24, 2008:
Dear Dr. Vinny,
Why is diammonium phosphate (DAP) added to fermenting wine tanks?
—Greg R., from the Internet
Dear Greg,
DAP—a water-soluble ammonium phosphate—is a yeast nutrient, resulting in stronger and more viable yeasts that in some cases work faster. Sometimes, fermentations slow down, or even get "stuck," stopping before all the sugar is converted to alcohol. These fermentation problems are often yeast problems—there can be something wrong with the yeast itself (old, weak, or a bad match to the grapes it's working with) or something in the environment (cleanliness, temperature) could be interfering with the yeast and preventing it from performing better. So DAP and similar products are used either to prevent fermentation problems or to fix them.
—Dr. Vinny
Do you have a question for me? Fire away! And don't forget to check out my archive.
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