Preparing your grape harvest

By Alain Touzaa, a Tom Press customer.

The grapes are ripening and you are perhaps soon going to harvest them.
Before giving you some advice about getting the best out of your grapes, let´s talk about the vine.
It is in the final weeks that the acid in the grapes transforms into sugar. During this period, you can still help the vine by thinning the leaves around the bunches. Sun exposition will be better as will air circulation. Why? Your seeds have grown and they are in thick bunches that touch each other. At night, when the dew falls, the grapes may dry badly and there is a risk that fungi may develop. Remove as few leaves as possible as photosynthesis is essential for good development.
Right. Are your grapes almost ripe? It is time to think about the material.


Clean carefully
Hygiene is essential throughout the process from grape to wine. A large majority of unpleasant tastes in wine come from contamination that can be avoided by sorting the grapes and cleaning your material thoroughly. Sacks, secateurs, buckets, grinders and presses must all be perfectly clean. Clean with water and rub the basket with a brush and leave it to dry properly.

Harvest in the morning
When the grapes are too hot, the alcoholic fermentation will start quickly and reach temperatures that are too high, burning the aromas!
Harvest when it is still cool and avoid overheating the grapes. In any case, above 15°C, the alcoholic fermentation will be spontaneous. This fermentation will release heat. If you harvest when it is cool, the fermentation will take place more gently and your wine will be richer.

Sort your grapes and grape them at the last moment
Remove rotten grapes systematically, remove stalks, leaves and most importantly grind at the last moment. Once crushed, the grapes become even more vulnerable. The contents are no longer protected and they will oxidise, making your wine acidic. Place in a vat (red wine) or press quickly (white wine).

Harvest what you can handle in one day
Generally speaking, you should limit the time during which the grapes are stored. If you are not sure that you can process your harvest the same day, leave the grapes on the vine. The best way to reduce the risk of contamination is by reducing the time during which your grapes are vulnerable, so you should not keep your harvest overnight before processing them. The vine is the best place for them.

Pressing: limit the pressing!
Pros use the term pressuring. Whatever you like to call it, the goal is to obtain the best possible juice. Your grapes are clean and all of the grapes were smashed during crushing, there are no more stalks to give an acidic taste: now you can press. Be careful: the skins and above all the seeds still remain. With a simple ratchet press like the one I use for my enjoyment, you can reach considerable pressure and if you press too hard, you will gather the acridness of the pips. These pungent and bitter notes are hidden by the sugar. You will not necessarily taste them when you taste the must that comes out of the press. However, they are present, and when the sugar transforms into alcohol, they may become predominant. Your wine will already have lost its roundness and velvety feel.
Limit the pressure and let the juice flow gently. When there is not much more juice, release the press and mix the marc to release pockets of juice that have been trapped in the dry matter before pressing again. This way, the yield will be satisfactory without exerting too much pressure.
To give you an idea of what not to do, remember the bad practices of the past. For what were known as ""table wines"", the goal was to produce as much as possible. The vine had to ""piss"" and the quality was low. The worst wines were rectified by chemists who were paid to perform miracles. Even with a screw press, you regularly obtain more than 100 litres of must for 130 kg of grapes! More in good years. You press twice to get the last drops. Things were different in the old days. Nowadays, nobody drinks a litre of ""table wine"" at lunch