Ripening

Ripening is a process in fruits that causes them to become more palatable. In general, a fruit becomes sweeter, less green, and softer as it ripens. Even though the acidity of fruit increases as it ripens, the higher acidity level does not make the fruit seem tarter. This is attributed to the Brix-Acid Ratio.

Ripening agents

Ripening agents speed up the ripening process.

They allow many fruits to be picked prior to full ripening, which is useful, since ripened fruits do not ship well. For example, bananas are picked when green and artificially ripened after shipment by being gassed with ethylene.

Calcium carbide is also used in some countries for artificially ripening fruit. When calcium carbide comes in contact with moisture, it produces acetylene gas, which is quite similar in reaction to the natural ripening agent ethylene. Acetylene acts like ethylene and accelerates the ripening process. Industrial-grade calcium carbide may also contain traces of arsenic and phosphorus which makes it a human health concern. The use of this chemical for this purpose is illegal in most countries.

Ripeness in viticulture

In viticulture, ripeness is the completion of the ripening process of wine grapes on the vine which signals the beginning of harvest. What exactly constitutes ripeness will vary depending on what style of wine is being produced (sparkling, still, fortified, rosé, dessert wine, etc.) and what the winemaker and viticulturist personally believe constitutes ripeness. Once the grapes are harvested, the physical and chemical components of the grape which will influence a wine's quality are essentially set so determining the optimal moment of ripeness may be considered the most crucial decision in winemaking.

There are several factors that contribute to the ripeness of the grape. As the grapes go through veraison, sugars in the grapes will continue to rise as acid levels fall. The balance between sugar (as well as the potential alcohol level) and acids is considered one of the most critical aspects of producing quality wine so both the must weight and "total acidity", as well as the pH of the grapes, are evaluated to determine ripeness. Towards the end of the 20th century, winemakers and viticulturists began focusing on the concept of achieving "physiological" ripeness in the grapes-described as a more complete ripeness of tannins and other phenolic compounds in the grapes that contribute to the color, flavor and aroma of wine.