Page "Winemaking" Paragraph 57

Whether the wine is aging in tanks or barrels, tests are run periodically in a laboratory to check the status of the wine.

Common tests include ° Brix, pH, titratable acidity, residual sugar, free or available sulfur, total sulfur, volatile acidity and percent alcohol.

Additional tests include those for the crystallization of cream of tartar ( potassium hydrogen tartrate ) and the precipitation of heat unstable protein ; this last test is limited to white wines.

These tests are often performed throughout the making of the wine as well as prior to bottling.

In response to the results of these tests, a winemaker can then decide on appropriate remedial action, for example the addition of more sulfur dioxide.