Grape concentrate is made by heating and boiling grape juice at a reduced pressure to eliminate 75 to 80% of the water naturally present in the fruit. There are a variety of sizes for concentrated wine kits ranging from 6.3 litres to 18 litres. In each case water is added back into the concentrate to bring it up to 23 litres of juice. 

Several qualities of the grapes which are valued in wine making can be lost during the concentration process. Especially aroma, colour, tannins and varietal character. 

The addition of invert sugar, which is sugar resistant to crystallization, is added to grape concentrate to prolong the shelf life and to work with the yeast to generate fermentation. Invert sugar is great for baking it does not make for great wine. Invert sugar can make wine taste thin with a tart and empty aftertaste.

Sometimes, to compensate for the colour lightening characteristics of invert sugar, some producers will add dies to the concentrate to deepen the colour. Some will include an additional package of tannin flavouring to make up for lost taste during the concentration process. Some even add artificial flavour.

For these reasons, wine kits made from grape concentrates will not taste the same as wine made from pure grape juice. Pure grape juice is essentially the juice that is extracted from wine grapes, before any major processing. It retains a varietal’s main organoleptic qualities and characteristics and transfers them to the wine.

Given a choice, always choose a pure juice wine kits with original sugars over concentrated wine kits to get a more full-bodied, longer lasting and better tasting wine.