Winery | Brewery | Distillery

The purpose behind cold stabilization is to remove all tartrate crystals from a wine during its fermentation stage. Tartrate Crystals are also called “wine diamonds”. They are a natural product of the wine, and form when the wine gets too cold. It is in essence cream of tartar, forming because of the temperature change. Think of sugar turning into rock candy and you’ll have a good mental image.

Tartaric acid is a normal grape acid. Potassium also exists in grapes, and when these two things bind together under chilly conditions, they form little potassium bitartrate crystals, which then settle to the bottom of the bottle. They’re completely harmless, and quite natural. The problem, of course, is with appearances.

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Cold stabilization

Since the tartaric acid and potassium are natural components of grapes, they cannot really be removed. To make sure crystals don’t form in the consumer’s home, therefore, the winemaker forces all crystals to form at the winery.

Usually the main stainless steel fermentation vessel for the wine has a cooling system on it. After the fermentation is complete, that vessel is plunged to near-freezing for 3 to 4 days to force the crystals to form. The crystals stick to the sides of the vessel, and when the wine is then removed, the crystals remain behind. Some winemakers argue that a portion of the flavor and uniqueness of the wine remains behind as well. Cold Stabilization is normally only done to white and blush wines. This isn’t because red wines do not form crystals – any wine will form crystals, since every wine is made from grapes containing the ingredients for crystals. However, since crystals only form when a wine gets very cold, red wines rarely show crystals, since red wines are served at a relatively warm temperature. They should never reach that cooler, crystal-forming temperature.

Low-pressure dimpled or channel jackets for glycol and water are available, also high-pressure flow of freon or ammonia. Both of these systems ensure continuous, precise control of temperature.

 

Dimpled cooling panels may be installed in tanks during fabrication or in storage tanks on-site at the winery. They may also be added to existing inefficient cooling jackets. Channel-jacketed tanks keep the wine chilled with a mixture of glycol and water circulating at low pressure.

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Dimpled cooling jackets

A practical method of cooling tanks for cold stabilization or for control of fermentation for smaller applications is with a portable glycol chiller.

This cost effective 3/4 ton unit was designed and proved to be very effective for Jeff Martin of La Frenz Wines.

At the other end of the scale we designed and installed a 222 ton computer controlled refrigeration chiller system for Kelowna’s new Sky Reach Place arena.

For chillers to walk-in coolers and freezers we would be happy to talk with you about your refrigeration needs and come up with a cost effective system to suit your needs.