I've picked my grapes, but I don't have any yeast yet. How long can I leave them before crushing them and starting the fermentation for white wine.
Fermentation is the process by which grapes are converted into wine, so you'll want to start the fermentation process as soon as possible after picking the grapes. If you don't have any yeast, you can crush the grapes and let them sit for a few days to allow wild yeasts on the grapes to begin the fermentation process. However, this can be unpredictable and may not result in the best wine. It's best to obtain some yeast and add it to the crushed grapes as soon as possible to ensure a successful fermentation. You can also try using a starter culture of yeast to help get the fermentation process started.