Brix

Brix (°Bx) measures the percentage of soluble solids (primarily sucrose) in a liquid. A refractometer is used to measure Brix in the field. Most supermarket tomatoes measure 4–5°Bx, while exceptional varieties like Sungold can exceed 9.0°Bx. Higher Brix correlates with richer flavor. Brix is used commercially to determine harvest timing and fruit quality grading.