Lots of that going on in the wine world right now. If you’re picturing yourself in a bathtub full of cold water, you’re not too far off. The term is literal, but there’s no water involved.
The cold soak is a technique that delays the onset of fermentation by keeping the must (crushed grapes) cool (yeast likes it warm).
If the grapes come in at night or on a very chilly morning, it’s just a matter of keeping it that way and with stainless steel tanks, it’s very easily done.
When the grapes come in warm, the most common way to chill the must down is to blanket it with dry ice (the solid form of carbon-dioxide).
The cold soak usually applies to red wine. It’s a good way to get some color, flavor and tannin from the grape skins without extracting bitter seed tannin. There’s no avoiding seed tannin entirely because alcohol is a solvent, so as per a recent post, it’s important that the seeds are mature – not too bitter – before they’re harvested. Continue reading