Rhubarb belongs to the buckwheat family. The rhubarb plant is a herbaceous perennial. Botanically, rhubarb is a vegetable, however, in use it is considered a fruit.
Only the leafstalk of rhubarb is suitable for human consumption. The leaf blade contains a high content of oxalic acid characterized by soluble salts and can be quite poisonous.
Fresh rhubarb is available throughout the year with the heaviest supplies marketed January through August. Most of the nation's supplies originate in Washington, Michigan and California.
The U. S. Standards for Grades of Rhubarb cover only "field grown" stock but can be used as guidelines for "hothouse" or "greenhouse grown" stock.
Grades of Rhubarb
- U.S. Fancy consists of stalks of rhubarb of similar varietal characteristics which are very well colored, fresh, tender, straight, clean, well trimmed and not pithy; which are free from decay, and free from damage caused by scars, freezing, disease, insects, or mechanical or other means. (See §51.3669.)
a. The diameter of each stalk is not less than 1 inch, and the length not less than 10 inches. (See §51.3669.)
- U.S. No. 1 consists of stalks of rhubarb of similar varietal characteristics which are well colored, fresh, tender, straight, clean, well trimmed and not pithy; which are free from decay, and free from damage caused by scars, freezing, disease, insects or mechanical or other means. (See §51.3669.)
a. Unless otherwise specified, the diameter of each stalk is not less than three-fourths inch, and the length not less than 10 inches. (See §51.3669.)
- U.S. No. 2 consists of stalks of rhubarb of similar varietal characteristics which are fairly well colored, fresh, fairly straight, clean, well trimmed and not pithy; which are free from decay, and free from serious damage caused by scars, freezing, disease, insects or mechanical or other means. (See §51.3669.)
a. Unless otherwise specified, the diameter of each stalk is not less than one-half inch, and the length not less than 8 inches. (See §51.3669.)
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