How is grape drying done?

The drying process is essential to transform fresh grapes into delicious raisins. Proper drying guarantees a longer shelf life for the grapes, preserving their sweetness, texture and nutritional properties.

In Chile, the dehydrated grape industry has experienced remarkable growth. The country's favorable climate and soils provide ideal conditions for growing high-quality grapes. Chilean dried grapes are appreciated for their intense flavor and their contribution to the world market.

Globally, the dried grape industry plays a leading role in healthy eating. Dried grapes are an excellent source of antioxidants, fiber, and essential nutrients. Its regular consumption is associated with health benefits, such as improved digestion and the immune system.

The drying of grapes is carried out by various methods, such as drying in the sun, in the air or by means of specialized equipment. These techniques make it possible to preserve the organoleptic qualities of the grapes, such as their characteristic flavor and aroma. The drying process with TROCKNNER dehydration equipment is carried out as follows

1. Warm up

During the drying process, if the grape directly enters a high-temperature environment, it causes the grape to experience a biological protection reaction, that is, the pores of the epidermal cells contract, the rind hardens, and the moisture remains inside. the grape. Therefore, at the initial stage of grape drying, sufficient preheating is needed, and the temperature should be gradually increased to prepare for a large amount of water evaporation. It is recommended to maintain the temperature at 35°C for 6 to 10 hours. When the temperature of the grape reaches 45°C it will be slightly hot. When the temperature of the grape reaches 45 - 48°C a superficial layer of water will appear on the grape.

2. Evaporation

The large amount of free water inside the grapes evaporates. At this time, the temperature should be increased to 65°C for 8 to 12 hours and should not exceed 70°C. In order to evaporate a large amount of water, pay attention to dehumidification and avoid the indoor temperature changing a lot, so that the water evaporates continuously. When wrinkles appear on the surface of the grape fruit, it indicates that the grapes are dry.

3. Drying

When the temperature inside the grape is uniform, this stage can usually be completed in 6 hours. Because there is not much moisture in the grapes at this stage, special attention should be paid to temperature control, it should not be too high, preferably 50 - 55°C. At this time, the relative humidity tends to decrease, and if it is more than 60%, it can still be drained. With the gradual balance of moisture in the grapes, the purpose of drying is achieved. Take care to remove dried samples in time.

4. Cooling

Baked grapes need to be ventilated and heat dissipated, and can only be stacked after cooling down. If the grapes just unloaded from the dryer are piled up in the cellar, because the grape itself has a lot of sugar, under the action of heat, the sugar ferments and easily deteriorates. The original pectin in the grape will also break down the gum in the fruit and the acid in the pectin. The grapes will inevitably become a mess, and the sugar in the grapes will change, bitter filaments will appear, destroying the grapes. Therefore, after baking, it must be completely cooled before it can be stored.

When it comes to quality, service and value. Count on TROCKNNER dryers!