Washington State University is offering free online training for cider makers on how to test tannin levels in apple juice. The training teaches cider producers how to analyze their raw materials so that their cider has a consistent mouth feel.
Tannin provides astringency, or a sensation of dryness in the mouth, but tannin levels in apple juice can be inconsistent from variety to variety and year to year. Each batch of juice should be tested.
The training, which will be hosted by Dr. Carol Miles, head of the hard cider program at WSU, Mount Vernon, explains how to perform the laboratory procedure for the Lowenthal permanganate titration technique, which also can be used to test tannin levels in grape juice, tea, and other beverages.
Register at http://breeze.wsu.edu/tannin/event/registration.html.