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Sunday, December 21, 2014

Making Good Wine: Fermentation Part Three (Red Wines)

If you are growing your own grapes the decision to pick rests entirely with yourself. Naturally, weather and ripeness feature in the decision making. At HHF this involves a casual walk through the vineyard with a refractometer testing select grapes from different locations. Experience says that the overall impression of ripeness will be a degree or two higher than the true end result. Why is not a mystery. Once the bunches are de-stemmed and resting in a fermenter the sugar levels of ripe bunches are spread across not so ripe bunches.

Other considerations are seed maturity i.e. not green and not too brown, a taste test by crunching seeds in the mouth give an indication. The skins should also feel a little silky to touch giving an indication that ripeness is at its peak.

When buying and picking grapes from a commercial vineyard timing is dictated by their activity. Usually their winemaker makes a call and getting a share means fitting in with them. You take what you are given.

A good way to encourage better quality is to triage the bunches as they are picked. Getting rid of an rot, shrivelled or green grapes and even any under ripe fruit. The tool of choice is a pair of short nosed scissors. Their stubby length but sharp pointy end allows easy gouging out of any unwanted berries. The handles a rubbery lined making them comfortable to use for extended periods.

Picking is best in early morning when the fruit is cool. Crushing and de-stemming can commence immediately. If the grapes have been transported from another vineyard the picking bins will go into a refrigeration unit while the crush pad is setup and any other chores are completed. There is a long day after picking which involves a lot of cleaning once the grapes a crushed and de-stemmed. An important task is to weigh everything as this is the basis for payment to the grower but is also the basis for future calculations of sulphur, Acid and Oak additions.

As the fruit is loaded into the crusher de-stemmer any good bunches are set aside to be added to the fermenter as whole bunches which are placed at the bottom. The bunches chosen are undamaged and don't have green stems nor dried brown stems. What is required is mature stems which will add some additional tannin complexity not green herbaceous flavours. The usual ratio is about 10% whole bunches but if it is a particularly ripe year more can be added. A bit of a guess really. In a an under ripe year 0% may be the choice.

Once crushed and de-stemming is finished the resultant fruit and juice is placed under refrigeration for 1-3 days. 30 ppm Potassium Metabisulphite is added. Ideally the cooling temperature should be about 7 C but using old freezers results in the outer fruit freezing. Not a bad thing as the freezing breaks down the skin cells helping release the colour.

This is a good time to drain off 10% of the juice for Rose. Exactly when depends on how much colour is wanted. Again a bit of a guess, but 24 hours is a good start. Experience has shown that a little oak added after fermentation of rose i.e. at the first racking adds a excellent flavour to the dryness. Rose is ideally fermented at 20 C.

Reducing the juice by 10% means there are more skins and less juice adding even more colour.

24 hours after crushing is a good time to run some tests. Sugar levels should be what is expected. If not here is the opportunity to add sugar in the form of plain white sugar. pH should be in the 3.4 to 3.8 range. If it is above 3.8 then the addition of Tartaric acid may be the solution. Ideally testing for Total Acidity (TA) is better but that requires some more equipment and chemicals. Something that most amateurs don't bother with but then some do. I find pH is a reasonable indicator as to where acidity lies. We invested in a pH meter rather than pH papers.

After the cold soak the fruit and juice needs to warm up and the yeast re hydrated. By lowering the temperature of the yeast gradually it is possible to add it to the fermenter early. Usually that will be at about 20C.

Ideally the fermentation temperature should reach and stay at 30 C but certainly don't let it go higher than 32 C. Plunging of the cap of skins should be performed 3-4 times each day. This helps add oxygen to the must and aids the yeast.

5-7 days of fermentation should be followed with 10 days minimum although a total of 21-23 days from Commencement of cold soak to pressing is ideal. Post fermentation is a good time to cover the fermenter with plastic wrap and inject some inert gas such as CO2. We use CO2 because we own a SodaStream which has a conveniently sized spear pint over which a plastic tube can be fitted. CO2 or other gas cylinders are expensive to buy and tedious to rent for short periods.

Usually if the skins have completely fallen from the surface it is a reasonable guide to press. Pressing slowly is advantageous in reducing the amount of unpleasant flavours that can be forced from seeds and stems. Always a good idea to keep the pressings separate for later use in blending.

We use a fine sieve to reduce the amount of solids being funnelled into the fermenter. The addition of oak occurs at this stage in the form of chips. We found that 50% French and 50% American to be ideal but no more than 6 grams per litre in total and less if the wine is lighter.

If there is another batch of red still fermenting the addition of skins from the just pressed batch will add complexity.

Some people rack the wine 3-4 times before bottling. We found that racking once about 40 or so days after pressing was sufficient to get rid of the gross lees which might impart unpleasant flavours. It is at this time that a decision to add more oak can be accommodated. Ideally a little more sulphur helps, lets say the rest of the 50ppm that we try to stick with.

Bottling commences from 8 months after pressing. Using a Bio Dynamic calendar we choose the best week in each month when turbidity is at its minimum. With reds there will always be some sediment as they age but I'd rather have a bit of sediment and decant . Filtering to me seems to eliminate some of the goodness in the wine that makes it a healthy part of a meal.

That is the short version so any questions?

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