Wine Production

Making good wine is a blend of knowledge, skill, and excellent grapes. This section includes resources on wine production, home winemaking, wine acidity, tannins, and enological additives. In addition, you’ll find advice on preparing for harvest season, managing sulfur, and handling grapevine diseases.

The Basics of Wine Production

Successful wine production starts with harvesting the grape clusters at the perfect moment. In general, the grape harvest season in the US is between August and October. The best time to pluck the grapes is typically based on their variety and the type of wine being made. It is important to remember that picking the fruit at optimal ripeness will determine the acidity and flavor of the wine.

Once the grapes have been plucked from the vineyards, they are sent to the winery. There, they are de-stemmed, crushed, and left to ferment.

Wine Fermentation

During fermentation, yeast converts grape sugar to alcohol and carbon dioxide. Typically, the optimal fermentation temperature for white wines is at or below 59°F and between 68°F - 86°F for red wines.

Experimenting with fermentation at lower temperatures can be beneficial for white, rosé, and other aromatically delicate varieties. Temperature control can improve wine quality and enhance aroma and flavor retention.

After the fermentation process is complete, the wine is transferred into barrels or tanks and the tannins and yeast are removed. Winemakers can choose to instantly bottle the product or let it age further.

Wine Acidity and Tannins

Wine has five basic characteristics – sweetness, acidity, body, tannin, and alcohol. Acidity and tannin are the most commonly confused features.

Wine acidity adds a refreshing taste, brings out the flavor of the fruit, and helps preserve wine. Grapes are naturally high in acidity, but other types of fruit, such as apples, may require the addition of acid (e.g. citric) before the fermentation process.

Tannin, on the other hand, is a phenolic compound found in the seeds, skins, and stems of wine grapes. It adds an astringent flavor, balance, and structure, allowing wines to age longer.

Troubleshooting Wine Quality

Winemaking can be rewarding, but it comes with its own unique challenges. In wine production, even the smallest of mistakes can affect the taste and quality of the end product.

Whether in the vineyard or the cellar, there are various things that can be done to ensure better wine. In the grapevines, diseases – like the Botrytis bunch rot and sour rot – can reduce quality and cause yield loss. Preparing for the possibility of incoming diseased fruits can help vintners make better decisions during the wine fermentation process and minimize damage.

Winemakers should further consider incorporating microbiology techniques, sanitation monitoring, and analytical labs.

For those eager to learn more, Penn State Extension provides a number of resources for (aspiring) winemakers. Educational courses and seminars – such as the Wine Quality Improvement workshop – are available as well.

How to Make Wine at Home

The home winemaking process is fairly similar to that of commercially produced wine. To get started, you will need several pieces of winemaking equipment, such as storage and fermentation containers, hydrometer, funnel, and tubing.

Besides equipment, you’ll need to choose a juice for the wine’s base flavor. The juice can come from grapes, but also from other fruits such as apples and blueberries. Discover more about the process with Penn State Extension’s Fruit Wine Production workshop.

Homemade wine usually requires around two weeks to ferment. Once fermented, the wine is filtered and can be consumed directly or stored for aging to acquire the desired flavor.