Concord grapes: Vitis labrusca

The Concord grapes is a robust grape cultivated from ancestral native species or a derivatives of a wild Vitis labrusca grape that could withstand the harsh New England weather. Concord grapes were first developed near Concord, Massachusetts by Ephraim Wales Bull in 1849.

It grew from a seed planted in 1843, which bore fruit in 1849. Prior to the appearance of the Concord, grape growing in Eastern American had limited success.

The only sugars are found in Concord grapes are glucose, fructose and sucrose, and the major nonvolatile acids found were tartaric and malic.

The Concord grape variety is chiefly used for the manufacture of grape juice. Approximately 96% of the juice made in New York state is prepared from Concord Grapes. Natural acidity, color and aroma of fresh grape berries provide quality in single strength Concord grape juice. Acidity above 0.85% results in juice that is too tart.

Hot pressing of the grapes is important to extract anthocyanin pigments, flavor components, amino acids, organic acids, sugars, minerals, tannins, and other ingredients.
Concord grapes: Vitis labrusca

How grape juice is manufactured

How grape juice is manufactured
The Concord variety is chiefly used for the manufacture of grape juice. The grape are washed in acid or alkaline solution, then in water to remove spray residues, then destemmed and crushed by mechanical means. The crushed grapes are heated to about 180 F to extract pigment from the skins, after which the heated materials subjected to mechanical pressure while enclosed on cotton press cloths. The juice is then filtered, pasteurized by heating to 1790 F, and stored in bulk in covered tanks at about 40 F. This provides for the separation of tartaric acid slats. The juice is then siphoned off from the tartrate and treated with enzymes, which break down pectin, or with casein for purposes or clarification. It is then filtered and bottled. The bottles are capped and then pasteurized by heating in water at 170 F for 30 min.

To produce grape juice concentrate, grape juice is subjected to heat and evaporation until concentrated. Volatile components can be recovered from the process, and they can be added back to the concentrate. The concentrated juice may be frozen in retail sized containers, or it may be shipped in large tanks to food processors for remanufacturing process.
How grape juice is manufactured