I used the whole packet (pictured below). It is enough for 5 gallons but I usually use the entire amount for 1 gallon, or divide it between two if I'm running low on yeast. You always want to have more than enough yeast or the wine will be sweet. Wine can be sweetened but not the other way around. Kinda like salt in cooking.
For this batch I used Red Star Pasteur Red which produces a very smooth dry wine. It likes to ferment for at least 3 months.
After adding the yeast I laid the lid on the bucket and the next morning before work.......
Notice the yeast is reacting? I give it a good stir......
And it bubbles and gives a satisfying sizzle. I observe the slight musty scent now and lay the lid on again. The next day....
Its a bit hard to see but there are now clumps of the thick foam on the surface. My house is cool in the winter and this slows the fermentation. If your situation is warmer you might get this overnight since the process is accelerated by an increase in temperature. Another good stir.....
And we wait another day after I cover the "must". During this time I sat the bucket on the edge of a heating pad covered by a thick folded towel. Yeast is happiest around 68 degrees Fahrenheit as a minimum. The object of primary fermentation is to allow the yeast to start and then quiet so that it doesn't blow off the airlock in the secondary vessel. Knowing when to transfer comes with experience. This particular wine I usually allow 3 to 4 stirrings then transfer.
The next morning...........
OH NO!! When I laid the lid on a piece of a tea towel was lodged underneath and the must was allowed too much air. This moldy substance smells like wet hay, which any country person will tell you is a sad state of affairs, but not a tragedy. I skim off all the white mold I can and immediately begin the transfer to secondary fermentation. The wine will probably recover, as does the hay in the field, so don't throw it out.
Stir it til the sugar dissolves and then add to my gallon jug.
Notice the water level in the air lock. After I put it on the jug in just a few seconds.....
The carbon dioxide that is released when the yeast is working begins to push the water up to escape. A very good sign this is! But if your wine doesn't do this immediately do not worry. It will be bubbling by the next morning most likely.
I cover the jug to keep the light out so the wine doesn't fade and I lay a wet dishcloth over the top just in case the yeast hasn't quietened to a steady fermentation. I learned this from experience of wiping down the walls. I would get home from work and the walls and everything would be covered in a fine spray of lavender mist. The good news is it washes up easily with warm water!
Now we wait. For weeks. Since this batch wasn't optimal I will "rack" (siphon) the wine off the "lees" (dead yeast and solids) in about a month. I'll know then how good the wine will be.