Wine advice

[DrHopper]

A friend has a grape vine and wants to have a go at wine. We should be able to get a gallon of juice. What is the target sg, will we need to add brew sugar. Also are there other additions needed to stabilise it and stop it tasting like mud! Ta

 

[tonyhibbett]

A typical sg of juice from UK grown grapes is 1060. Due to the presence of suspended pulp and minerals which also influence the hydrometer reading apart from sugar, treat 1060 as 1053. It's best to check the acidity, which can be rather high in the uk. With the aid of a press, 1 kilo of grapes should yield about 600 ml of juice. However, if you leave the crushed grapes overnight with some pectolase, (with sulphite, to be on the safe side) it is possible to increase this to 700 ml. If making red wine, leave the skins in for 3 days before pressing, but remove the stalks first. I normally add sugar to bring the sg to 1090, typically 400 g to the gallon. The resulting wine depends on the variety of grape. Black Hamburg does not make a good wine, but cabernet sauvignon does!

 

[chewie]

You either need to use a refractometer to measure the juice as is from a trial grape or wait until there all pressed and measure it then with a hydrometer and seeing what you end up with, the advantage of using a refractometer is you can hold of picking the grapes until they are full of sugar whereas a hydrometer is more down to luck.

 

[tonyhibbett]

It's best to take a few readings as some bunches ripen more slowly and there are variations within bunches too. I recently tested a single grape and got a reading of 18 brix, but the final juice was down to 15. Another good test is taste. A fully ripe grape contains much less acid than an under ripe one. Unfortunately birds are very good at selecting the ripest grapes!

 

[DrHopper]

Cheers all. We added about 750 g and a couple of litres of cheap spring water and got it to about 0.085. Left on the pulp over night with a Campden, then racked into a demijohn with a gen purpose red wine yeast from the lhbs. Should be interesting! I am a hardened beer brewer but this is all new!