The standard onion has an eight rating, while "sweet onions" have a two or three rating on the scale. The lower the score or scale the more "sweet" the onions are rated. Anything less than five is considered a sweet onion. The Vidalia onion variety is considered sweet and must have a score of 5.0 μmol/g_fw or less.^{[citation needed]} The Supasweet onion (usually grown in Lincolnshire, England) registers 1.5 to 2 on the scale. A standard brown onion is usually in the range of 6–7 out of 10.

Soil type, rain, and sunlight affect the pungency in onions and garlic and, therefore, their score on the pyruvate scale.

• Scoville scale

• The National Organic Program — by the USDA^{[failed verification]}