Hi brewfrog. Not sure what you mean. Whisky is distilled and you cannot then ferment whisky. You can ferment sugar but sugar won't ferment to "whisky". It might make a tasteless wine. Corn won't ferment unless you have some means to break down the complex carbohydrates into simpler sugars that a yeast can eat. That might mean adding enzymes which is why brewers use malted barley.
A cup of sugar will contain about 8 oz of sugar and 8 oz of sugar will raise the gravity of water (when making 1 US gallon about 20 points. Twenty points (1.020) will ferment to give you a wine of about 2.6% ABV. That's about 100 ccs of alcohol in every gallon . So you are talking about... oh I don't know, about 1/3 of a cup of pure alcohol in that gallon of "wine"
You could use bread yeast and that would have no problem with your cup of sugar. Or you could wine yeast. Not sure why you would want to use distillers yeast. But I am not sure why anyone wants to use turbo yeasts. Either you brew beer or you make a wine if you plan to distill. Neither need "turbo" yeast. Neither benefit from anything but ale or wine yeast. But your experience may be very different
Less strong would not be considered an alcoholic drink. Your "whisky" will be about 2.5 % ABV; a store bought lager is likely to be about 3 or 4 %, a cider may be 5%, most wine is about 10 -12%, Drinkable spirits like scotch, vodka or gin is likely to be around 40% alcohol by volume (ABV)... You say that your parents would get mad... Are you old enough to be making wine? In the US the minimum legal age is 21.
But I am not sure why anyone wants to use turbo yeasts. Either you brew beer or you make a wine if you plan to distill. Neither need "turbo" yeast. Neither benefit from anything but ale or wine yeast. But your experience may be very different
Is turbo yeast actually good for anything? I have never used it but have yet to see a good comment about it, about anything, anywhere. On the face of it it makes me wonder if it is a "newbie trap" to think you'll get super alcoholic drinks (mead for example) but in fact all I read is you get really awful-tasting crap. Or is it purely to make sugar washes for distilling? Although why would you want to distill a sugar wash for drinking? Then again it widely available, so someone must be using it!
I suspect - but don't know for certain - that turbo yeast is cultured to make ethanol that can be distilled very quickly and very easily with musts and mashes that no one would think to turn into wine or ale. And if the final product is "moonshine" then the alcoholic substrate is viewed as raw material and not the source of a fine brandy or scotch or even a perfect vodka. Turbo yeast is packed (I believe) with all the nutrients that are likely to be required by the yeast and almost certainly missing from the sources of refined sugar. Isn't this one reason why such users of TY use active charcoal to remove all the unwanted flavors produced in the ferments they then distill?