So with the success of my first vinegar a rose wine vinegar I decided I’d try making a fruit vinegar. Raspberries were on sale recently and raspberry vinaigrettes are delicious so that made my decision easy. Because I recently refreshed my 1.5 year old grape yeast water I decided I’d speed the first fermentation up by inoculating the raspberries with some about 2 tbsp of the grape yeast water. So into a jar went the two containers of raspberries. In a ratio of 500 g of fruit to 66 g of sugar, added sugar and enough water to cover the fruit. You want to use a jar that will allow the fruit to rise quite a bit as they ferment. I didn’t do this and lost a fair amount of the raspberry water initially until I transferred half of the raspberries and water into a new jar.
Within a day or two you will have vigorous fermentation of the sugars into ethanol by the wild yeast.
Next, swirl this daily until the fruit is no longer floating and bubbling, this indicates that the first fermentation is complete. Another indication that this first stage is complete is that the water is clear. Apparently for apple vinegar the water will never be clear so you cannot use that indicator as a sign of the completion of this stage.
The fruit solids are strained out and now the jar of raspberry wine is left to spontaneously start the second fermentation of ethanol to acetic acid. This is an aerobic fermentation so you must allow the water to be exposed to air for this to occur. I covered the jar with gauze kept in place by a rubber band. The Acetobacter needed to ferment is naturally in the fruit so it is already there in the raspberry wine so this should start on its own. If I had enough vinegar mother I could speed this up by placing the mother into this jar, however, I don’t have a mature vinegar mother yet so I’ll have to wait and see if this second fermentation will start on its own.
The pH today is 3.5 and the target is 2.8.