The Specific Gravity
The fermentation should occur at a constant temperature of 21°C (72°F) and will take anywhere from 7 – 12 days in total. Start to monitor the progress of the fermentation by taking readings with the hydrometer at day 5.
When the specific gravity is below 1000, (i.e. 995), then proceed with the racking (siphoning). If not, allow the wine to ferment longer until it reaches a specific gravity (S.G.) below 1000.
If the wine takes longer it is a good idea to gently “swirl” the carboy to move the viable yeast around the must inside. Remember that the closer the specific gravity is to 992 the drier the wine will be, because less residual sugar remains
Once the specific gravity (S.G.), is below 1000, siphon the wine off of its sediments into sterilized pails or another carboy (this is called racking).
Racking the Wine
First, siphon the wine off of its sediment into a 23L pail, then apply the stabilizer (1 tsp/22L wine mixed with 100 ml of hot water) to help prevent oxidation and bacterial infection. Now you need to move the wine into an airtight vessel. The best, and cheapest way is to just clean out the canisters the juice came in. Tilt them back and fill to the beginning of the spout, squeeze any air out and screw on the cap. Otherwise, siphon into a 5 gallon glass carboy and add the bung and airlock.
Remember, airspace at this stage is BAD. There should be less than an inch of space between the bung and the wine.
Oaking – Now is the time for the second regimen of oak. Add the remainder of your oak into your vessel. The majority of the oak flavour will come at this stage as it sits on the oak chips for the next 3+ weeks.
Cold Stabilization & Fining
The wine should be placed in a very cold spot, like the garage (in the winter) a fruit cellar, or any fridge. You want to aim for somewhere between +5°C to -5°C (41°-23°). The wine should sit in this cold place for at least 3 weeks. If it stays for longer, it should be racked again every 3-4 weeks. When the wine has been racked 4 times, stabilizer should be used again. Red wine will clarify in about 3 months.
It is also quite normal to see crystal deposition on the sides of the carboy. This is the precipitation of potassium bitartrate which is a naturally occurring substance in grape juice. The longer a wine is aged in the cold, the more crystals will fall out. This means fewer crystals will precipitate in your wine bottles.
Clarifying White Wine (Optional)
White wines can be harder to clarify. Using a combination of gelatin and Kieselsol at racking can greatly assist white wines in clarifying. Do NOT use gelatin and Kieselsol on red wine as it could potentially strip the colour of the wine.
Mix ½ tsp of gelatin with 200 ml of boiling hot water. Stir for a minute and let sit for 10-20 minutes. Siphon the white wine from its fermenter into a pail. Add the stabilizer (1 tsp/22L wine mixed with 100 ml of hot water), and then add the gelatin once it has sat for the required 10-20 minutes. Wait another 10 minutes and then add 1oz (28g) of Kieselsol. Finally, rack into an airtight container and follow cold stabilization instructions.