September Edition, ROUNDTABLE: Cold Soaking
Cold soaking, also known as cold maceration, is a common method used by winemakers to extract colour and flavour from mostly red grape skins.
Misha’s Vineyard Winemaker Olly Masters was invited to contribute to this roundtable discussion in the Australia & New Zealand Grapegrower & Winemaker Magazine.
What are the main reasons that you cold soak?
“Generally all our Pinot ferments start naturally. By cold soaking we generally avoid some of the volatile acidity issues you can see otherwise. I also prefer the tannin
integration that extended total tank time gives — cold soak is a good way to do this, i.e., avoiding oxidative opportunity. ”
Which varieties do you normally subject to cold soaking?
“We usually just do cold soaking with Pinot Noir. We do give some of our whites varying levels of skin contact, Pinot Gris and Riesling being the main ones — but generally only for a few hours.”
From where do you source the grapes that you cold soak?
“All Misha’s Vineyard fruit is sourced from our own single vineyard site on the Bendigo Station in Central Otago which is a cool climate area, and uniquely New Zealand’s only semi-continental grapegrowing area.”
Do you cold soak as a matter of course or are there certain parameters that must be reached first before you make the decision to use it?
“Generally our night time temperatures and fruit condition at harvest allow us to cold soak without extra chilling. Depending on vintage, ambient temperatures with the initial cold soak might be anywhere from 8-12°C.”
Describe your cold soak methods.
“Cold soak is a method we use often use and is generally applied in conjunction with all other techniques, such as whole bunch or high whole berry percentages. Our normal ferment volume is approximately four tonnes in a single skin, open top tank with a removable lid. This size allows for a good ferment profile temperature-wise, without too
much intervention energy wise. The ambient temperatures and fruit condition mean no further chilling is necessary to hold the ferment off. Typically, a 30pm S02 addition is made at crush and CO, is used to give an inert juice environment prior to ferment initiation. After five-seven days we expect to see some ferment activity starting. Later on in vintage, ambient temperatures may have cooled to the point where some heating is applied through drop-in plates or external wrap electric pads.”
What have been, or are, the challenges in getting the most out of cold soaking and how have you attempted to overcome them?
“Occasionally early vintage, the ferment fruit condition (i.e. physically fragile or a warmer temperature) means there may be a bit more VA development than we accept, in which case we would probably inoculate with a commercial yeast.”
Once cold-soaked wines have been in bottle for a time, have you noticed any differences in quality compared with non-cold soaked wines?
“All our Pinots receive a degree of cold soak so direct comparisons aren’t possible. We do believe it gives a more elegant palate structure and allows better
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