Bone char is a kind of "natural carbon" made from the bones of cattle. These cattle usually come from Afghanistan, Pakistan, India, and Argentina. It is sold to traders in the Scotland, Egypt, and Brazil who them sell it back to the US sugar industry. (Don't worry - the Eurpoean Union and USDA heavily regulate bone char and only accept it from countries deemed BSE-free).
Basically, bone char is used as a decolorizing filter to give sugar cane its white appearance. It's a filter. Of course, there are other filters that could be used - granular carbon and an ion exchange - but for some reason, people still choose to use bone char.
It's not just white sugar that's filtered by bone char, so you want to watch out for that. Brown sugar is molasses added to white sugar, so companies that use bone char in the process of making white sugar often use it when making brown sugar as well. Powdered sugar (or confectioner's sugar) is just refined sugar with cornstarch, so again, when made by a company that uses bone char on regular sugar, they usually use it on their powdered sugar as well.
As far as brands go, you're not safer with a store brand. Stores by their products from multiple different refineries, so it's impossible to determine if their sugar was filtered with bone char or not. Beet sugar is never refined with bone char, so that's an option.
Here are some companies that do NOT use bone char:
[FONT=tahoma,arial] Monitor Sugar
2600 S. Euclid Ave.
Bay City, MI 48706
Tel.: 517-686-0161
Fax: 517-686-2959
Web: www.monitorsugar.com
Florida Crystals Corporation
P.O. Box 471
West Palm Beach, FL 33480
Tel.: 877-835-2828
Fax: 516-366-5200
Web: www.floridacrystals.com
Western Sugar
Western Sugar is a subsidiary of Tate & Lyle (formerly Domino sugar) which does use bone-char filters. However, Western Sugar makes only beet sugar, which does not use bone-char filters.
7555 E. Hampton Ave., Ste. 600
Denver, CO 80210
Tel.: 303-830-3939
Fax: 303-830-3941
Web: www.westernsugar.com
And here are some companies that DO use bone char:
[FONT=tahoma,arial]C&H Sugar Company
2300 Contra Costa Blvd., Ste. 600
Pleasant Hill, CA 94523
Tel.: 925-688-1731
Fax: 925-822-1061
E-Mail: consumer.affairs@chsugar.com
Web: www.chsugar.com
Savannah Foods
P.O. Box 335
Savannah, GA 31402
Tel.: 912-234-1261
Tate & Lyle North American Sugars Inc. (formerly Domino Sugar)
1100 Key Hwy. W.
Baltimore, MD 21230
Tel.: 1-800-638-1590
Fax: 410-783-8640
Imperial Sugar
P.O. Box 9
Sugarland, TX 77487
Tel.: 1-800-727-8427
Web: www.imperialsugar.com
Refined Sugars Inc.
1 Federal St.
Yonkers, NY 10702
Tel.: 914-963-2400
Fax: 914-963-1030
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