Reasons for moldy homemade wine

A: Because the grape skin is in contact with the air for a long time, the bacterial growth is too fast, resulting in mold. Treatment: remove the moldy skin grapes, pay attention to not contact with the wine, get clean and stir 1 to 2 times a day, so that the skin to ensure that the moisture can be, only until the fermentation is complete.

Second: may be in the brewing process and oil contact, or containers are not clean resulting in mold, treatment: remove the moldy, do not shake the top layer of wine removal! After the observation of 2 days, did not continue to mold can continue to ferment, if the mold again, then declared homebrew failure!

Third: the grapes are not fermented at all, the sugar is too high and lead to mold, treatment, add live yeast.

Ways to avoid moldy homemade wine

First: choose the grape raw materials to try to remove the rotten fruit, moldy fruit, cracked fruit.

Second: After washing the grapes with water, be sure to? air-dried? Grapes, there can be no water.

Third: The temperature during fermentation is preferably between 26 and 28 degrees Celsius, and fermentation needs to start quickly.

Fourth: After 7 to 10 days of fermentation at a time, filter debris (grape skins, seeds, wine sludge, etc.) in a timely manner.

Fifth: after 1 month of secondary fermentation, filter the puree in time and make sure to fill the tanks where the wine is stored (to prevent oxidation).

Sixthly: the tanks should be emptied once every 3 to 5 months to remove the sludge and fill the tanks with wine.

Seventh: wines made from non-specialized wine grapes should ideally be consumed between 4 months and 1 year after the completion of the second fermentation.

Eighth: During primary fermentation, once you feel the fermentation stops, you can add a little bit of sugar into it to see if the yeast decomposition is finished, and try to make the yeast in the grapes to finish the fermentation, so that the wine's alcohol level will be higher (preferably up to 12 degrees), which is easy to store for a long time in the future.

5 things that can ruin your wine in the bottle

1. Oxidization

Oxidization is both the friend and the enemy of wine. A small amount of oxidation gives wines the complex flavors we love, such as vanilla, smoke, and dried fruits, but too much oxidation can lead to a darkening of the wine's color and a souring of its taste. Just as an apple turns brown immediately after being sliced, wine grapes react with oxygen from the moment they are pressed, and oxygen affects their flavors, aromas and color.

You can tell if a wine is over-oxidized by its color. A bright red rim or nearly clear white wine indicates that the wine is normal, but a brown color indicates that air has entered the bottle. On the palate, over-oxidized wines taste strange and acidic, with flavors of unfresh or unripe fruit or dried fruit.

2. Microorganisms

Microorganisms can also grow silently in wine. Sugar and yeast attract uncountable sugar-feeding . Bacteria that not only don't produce alcohol and good wine, but also bring out strange flavors. Brettanomyces, Lactobacillus, and Acetobacter are three common bacteria found in winemaking that radically alter the flavor, aroma, and aging potential of wine.

A small amount of brettanomyces can add earthy aromas and distinct character to a wine. Lactobacillus, the bacterium that gives yogurt and sourdough bread their distinctive, pungent flavors, can give wines a creamy taste in small amounts, but in excess, wines can be boring, so winemakers have to keep a close eye on them as they make their wines.

The most common problem in wine cellars is the growth of bad bacteria, but such problems can be quickly countered. Because bad bacteria feed on sugar, winemakers can remove them with strong yeasts, snuffing them out before they can do major damage to the wine. Bacteria can also be removed by using a reverse osmosis machine that keeps the wine from spinning rapidly in a centrifuge, but this practice can also seriously alter the flavor of the wine, so most winemakers only use reverse osmosis machines to remove bacteria as a last resort.

If your wine smells like dirt or nail polish, it's been damaged by bacteria. The flavor is not noticeable enough to drink, but if it tastes weird, it's time to pour.

3. Interrupted fermentation

? Interrupted? Fermentation means that the glucose has not been fully converted into alcohol. This is good for winemakers who want to produce sweet wines, but the remaining sugar in the wine can often taint the wine as well, since sugar feeds all the harmful bacteria. Without careful inspection, these bacteria can destroy the wine or turn it into something else entirely.

Imagine you buy a dry white Sauvignon Blanc with a sage aroma and it suddenly smells like horse stables or sauerkraut? If so, most customers won't buy this wine again, so slow or incomplete fermentation poses a major risk for big brands.

Strong yeast strains can address slow and incomplete fermentation, but winemakers need to use them on a case-by-case basis and supervise the wine closely, adding them in a timely manner before the bacteria interacts with the rest of the delicious, pure wine.

4. Smoke pollution

Wildfires ravage the western United States every year, destroying not only vast tracts of forest and homes, but also grapes. Smoke from forest fires often lingers in the valleys of many wine-producing regions for weeks, eventually seeping into the skins of the grapes and destroying their flavor. Because the skins have stomata, they gradually absorb the flavors from the smoke, giving the wine a musty smell.

Since most of the contamination occurs on the skins, it is sometimes possible to salvage the damage by using these grapes to make rosé rather than red wines.

5. Impurities

Impurities include bugs, leaves, twigs, and even birds, which sometimes ferment with the wine. Although wineries usually go to great lengths to avoid impurities during fermentation, it is inevitable that a spider or two will fall into the barrel. Thanks to modern, advanced filtration systems, we don't see bugs in our bottles, but its fragments begin to alter the wine even before it's filtered.

A few ladybugs, for example, can contaminate thousands of liters of wine. During fermentation, bubbles and chemical reactions mix the flavors and colors of the grapes, grape seeds, and other substances (including ladybugs, twigs, and leaves), often giving the wine a strange astringency reminiscent of unripe fruit flavors.