Sunday, April 8, 2012
Where 'normal' wine vinegar starts with wine, which then acetifies courtesy of acetobacter converting alcohol to acetic acid, traditional balsamic is a different pathway. Instead of starting with grape juice fermented to wine, the start point with balsamic (most of the time, not counting the commercial, short-cuts processes) is unfermented grape juice that is cooked out over flame to make musto cotto. Reduced to about half of the starting volume by the slow boiling process, the cooled must is settled & transferred to barrel, along with a small amount of gluconobacter culture (a story in itself). Unless you already happen to have some balsamic & bacteria in the bottom of that barrel already.
Gluconobacter are a group of bacteria sometimes found in combination with types of acetobacter, but they operate quite differently. Where acetobacter eat alcohol to make vinegar, gluconobacter eat some kinds of sugars while they make acid. So no alcoholic fermentation needed in the traditional balsamic process.
From hand-picking sauvignon blanc grapes from Quarry Hill, to foot-crushing & basket-pressing the fruit, then settling & filtering the juice, cooking it out in my 92 litre stainless steel pot on a heavy-duty metal frame wok-burner over a couple of days to make the musto cotto... it has been a fascinating learning process. Not least about the hazards of do it yourself gas fitting.
Now the hard part. Staying hands-off that little barrel & let the gluconobacter do the work, racking & transferring down the line once a year. In six years time, perhaps something good. Though traditional balsamico from Modena takes 12 years...
The image above is a close shot of some of the 32 jets on the Mongolian wok burner, with the 92 litre stainless steel pot of must cooking out on top. Beautiful to watch at night, if a bit noisy from the air-mixing Venturi effect the system uses (sounds a little like a jet engine when it gets going).