Why does home canned tomato juice usually separate?
Home canned tomato juice usually separates because it is made by the "cold break" method. The tomatoes are crushed before they are heated through. As soon as they are crushed, enzymes start to break down the pectin that "cements" tomato cells together. Commercially, tomatoes are heated nearly to boiling in a matter of seconds, using equipment not available to consumers. Because the pectin holding tomato cells together remains intact, a thick bodied, homogeneous juice is produced. The best that can be done at home is to heat quartered tomatoes quickly to boiling temperatures while crushing. Make sure the mixture boils constantly and vigorously while you add the remaining tomatoes. Simmer 5 minutes after all tomatoes are added, before juicing. If you are not concerned about juice separating, simply slice or quarter tomatoes into a large saucepan. Crush, heat and simmer for 5 minutes before juicing.
Barbara Willenberg, Nutritional
Sciences, University of Missouri-Columbia
Last update: Tuesday, May 05, 2009