i am making some wine and i couldnt get to the brewshop so i used bread yeast how long should i let it ferment

Bread yeast doesn't flocculate...in other words, when it's done doing its thing, it doesn't fall to the bottom. It stays suspended in the beer/wine/brew. As a result, it is very difficult to clarify and will taste yeasty.

There's dozens of varieties of wine yeast besides champagne yeast, so don't get hung up on that one. It will give a kick, however, as it's more alcohol tolerant than most people think...up to 14% if you do it carefully. Due to the lack of flocculaton affecting the taste, it's not used for wine or beer. However, a number of whisky distilleries use bread yeast to ferment their whiskey washes.

I have done that with bread yeast and I don't recommend it because your wine will have a heavy yeasty flavor. Wait to get the proper wine making yests for the type of wine you are making.The fermentation times will be about the same with either type of yeast as fermentation stops after all available sugars have been converted into alcohol, or, the alcohol content reaches 18% - 19% which kills off the yeast and fermentation then stops.

If you use baker's yeast, it could end up tasting yeasty. Other than that and the alcohol content as stated above, observe the fermentation rate (how long it takes a bubble to break out of the airlock) to know if it's done. Temperature affects the speed of fermentation more than the type of yeast usually does.

If you haven't started yet, I encourage you to wait until the brewshop is open. The yeast to make wine with, generically refered to as "champagne yeast" has a higher tolerance for alcohol (~12 % alcohol) than other yeasts; it takes longer to die because of alcohol toxicity & so as it continues to live longer it makes more alcohol. Bread yeast will die sooner (~6% alcohol) & leave more sugar unfermented - the wine will taste sweeter & somewhat unfinished.

;-)