Even using baker's yeast, the finished wine should not be unpalatable, especially if you pour it off the sediment into a fresh container and rest it for a few weeks before drinking. Alternatively, you can harvest live yeast from fresh muscat grapes: Crush five or six perfectly ripe grapes in a small glass bowl. Pour in enough grape juice to cover the grapes and cover the bowl with a saucer. Leave in a warmish place overnight. Next day, follow my method exactly but adding the contents of the small bowl in place of the dried yeast. Note- this is not guaranteed to work every time and there is a small risk of spoilage, but it can give excellent results, much better than baker's yeast ever will.