Brix = % soluble solids by weight as measured by refractive index (bending of light) relative to sucrose in pure water). 1 degree Brix = 1% sucrose by weight. The Brix scale is used to measure the amount of Water Soluble Solids in a juice. The main contributors to Brix readings in grape juice are the naturally present sugars (glucose & fructose). Acids (tartaric and malic), anthocyanins and other polyphenols, potassium and other minerals, and pectins, may also make a small increase in the Brix value, since these compounds affect the refractive index.
WSS = Water soluble solids, those carbohydrate and acid based solids that dissolve in water, often synonymous with Brix. The main contributors to WSS readings in grape juice are the naturally present sugars (glucose & fructose). Acids (tartaric and malic), anthocyanins and other polyphenols, potassium and other minerals, and pectins, may also make a small increase in the solids value.
ISS = Insoluble solids, typically complex carbohydrates, tartrate complexes, and polymerized compounds from fruit skin and pulp that are not soluble in water.
Titratable Acidity = a measure of the total amount of available hydrogen ions (from acid) in a sample. It is measured by titration (neutralization with base to specific endpoint pH) and it is typically reported as % citric or tartaric acid (weight per weight or weight per volume).
pH = a logarithmic quantification of the degree of acidic or basic nature of a sample. pH scale = 0-14 with 7.0 = neutral and <7.0 = acidic and >7.0= basic. Juices tend to be pH 2.5-4.5 depending on type. Grape juice tends to be 3.0-4.0.
Color = For purple or red grape juices, Welch’s measures color as absorbance units at 520 nm per gram of sample, corrected for the dilution volume and measured at pH 3.2.
Density = weight per unit of volume, typically reported as pounds per gallon or milligrams per liter.
Turbidity = measurement of cloudiness or haze in a liquid sample. Reported in various units, Welch’s uses NTU or Nephelometric Turbidity Units. A Nephelometer measures the amount of light scattered in a controlled way.
NFC = Not from concentrate juice, or as-is pressed from fruit and not reconstituted from concentrated juice.
Concentrate = water is removed from single strength juice by application of heat & vacuum to reduce the volume, stabilize the fruit juice solids and simplify storage and transportation of juice.
Essence = volatile flavor components captured during concentration and either stored separately or added back to concentrated juice.
Soda Base = a concentrated blend of juices, sugars, acids, and flavors that are used to make single strength sodas when carbonated water is added.