When making wine at home from a wine ingredient kit such as WinExpert or Cellar Craft the instructions usually tell you to prepare the ingredients and to sprinkle the yeast on top of the must prior to covering. Sometimes the instructions will also tell you to wait 24 hours prior to sprinkling the yeast.
However, when reading texts (or the back of the wine yeast packet) they will often recommend that you rehydrate the yeast prior to pitching it into your wine must. This generates quite a few questions from both home winemakers and home brewers.
The simple answer is that the more yeast cells that can be delivered into your must or wort, the better the chance that your wine or beer will get off to a successful start.
The not-so-simple answer is that rehydrating the yeast is not as simple as adding water and pitching it into your fermenting bucket. There are many factors involved in the rehydration of yeast including: using the correct amount of water (the Lalvin people suggest that you add the yeast to water weighing 10 times the weight of the yeast) and having the water at a very precise temperature (the range suggested is that the water be between 104 and 109 degrees Fahrenheit). Without going into a long description, the yeast hydration will fail if the water is either too cold or too hot.
Now the easy part--just sprinkle the yeast. Although you will have fewer yeast cells at the start (hence a slightly slower start) they will reproduce rapidly and without all the possible wrong turns that can occur with rehydration. How much yeast do you need? We use one packet for a batch of yeast (anywhere from one gallon to six gallons). Here at BlueStem Winery we start 50 gallon batches with 30 grams (equivalent to 6 packets of Red Star yeast) of yeast and we do not rehydrate--we sprinkle!
If you are looking for a prompt, friendly, reputable and reliable source for your wine making supplies or your home brewing ingredients we would appreciate your consideration. We are on the web at www.bluestemwine.com with a complete line of winemaking equipment, supplies, and ingredients and we also have a complete line of home beer making equipment, supplies, and ingredients for the home brewing enthusiast. We put together our own line of home brew ingredient kits (called BlueStem's Best) and we sell three lines of winemaking ingredient kits including those from Cellar Craft (we stock most of the Showcase line, a few if their dessert wine kits and several of their Premium 6-week 16 liter kits from their Regional Classics and Global Series lines), those from WinExpert (we stock about 80% of the wine kits available from WinExpert including from their Selection Original, Selection International, Selection Estate, Island Mist, Vintner's Reserve and World Vineyard series wine kits) plus we have our own brand of fruit wine kits with or without the necessary winemaking equipment for 3, 5 or 6 gallon batches of your favorite fruit wine.