Storage Of Grapes

The annual production of table grapes in the world is 16.5 million tons. Production areas are China, Turkey, Europe, Brazil, Chile and the United States. Popular grape varieties include Seedless Thompson, Seedless Flame, Seedless Crimson, Red Globe, Seedless Ruby, Seedless Red, Musket, and Sugraone.Long-term storage starts with excellent grape quality as well as strict harvest and storage protocols.

Grape Harvest

Before storage, rotten and damaged fruit is separated and removed. Correct harvest time depends on local quality classification, percentage of SCC (% Soluble Solids Concentration), sugar/acid ratio and color. (High sugar level provides improved storage results that would be more favorable under Controlled Atmosphere (CA) conditions).

CA / ULO Storage Of Grapes

Collected grapes should be taken to a 'pre-cooling room' at 4°C within half an hour after harvest. Grapes should be sorted and repackaged within a maximum of 4 hours. This has an extremely significant effect on the storage result.

The next step is to bring the grapes to a final storage temperature of -1.0 to 0°C and a relative humidity of 90 to 95%. Air velocity of approximately 20 to 40 feet per minute (FPM) during storage is recommended. Read our protocol on grape storage

Storage Of Grapes

Botrytus and SO2 Application

Storing grapes under Controlled Atmosphere (CA) conditions does not necessarily extend storage time, but quality often improves. The success of CA storage largely depends on the grape quality at the beginning of the storage period. In addition to the decrease in respiration, the decrease in moisture loss due to the effect of the higher CO2 level in the cooling tank or the Palliflex hose structure to stop the growth of fungi is an important factor of the positive effect on table grapes. Table grapes are extremely susceptible to a fungus called Botrytis, which often causes quality loss.

SO2 (sulfur dioxide) is applied to grapes to prevent Botrytis infections. In the absence of CA conditions and no SO2 treatment, Botrytis can occur in as little as 1 - 1½ months (depending on the type and quality of the grapes).