How many pounds of grapes does it take to make a barrel of wine.
A general rule, you need 800 pounds of fresh grapes still on the stems to make a 59-gallon barrel of wine.
What are the risk in using "wild" yeast for fermentation?
I'm not a fan of so-called natural fermentations, winemakers that solely trust ambiant yeast always seem to end up with fungi to find there way into the wine giving off taste as well as the smell. Commercial yeast strains have been bred specifically for the purpose of eating 20-30g of sugar before they are poisoned by 11-17g of ethanol. The cost of yeast to make your 6 gallon batch runs 95 cents it is not worth the trouble.
What are the most common "rookie mistakes".
Picking grapes to early or to late.
Inappropriate must adjustment ( dont' tweak your wine so much)
Not understanding the power of oxygen and spoilage microbes.
Keeping inadequate records.
What is sorbate.
Sorbate comes from sorbic acid. Sorbate is authorized for winemaking use in almost every country. Sorbic acid is not very soluble in water, it inhibits refermentation from accurring when sugar is added back into wine at bottling, or can stop fermentation prematurely to retain a certain level of sweetness.
If you have any questions email me and I shall look into the answer.