Fermentation slowing

Check out Jack Keller's site regarding blueberry wine.

He says its typical for fermentation to slow if you don't add yeast nutrient and energizer. Blueberries are just like that, he says. I used 3 lbs of blueberries with other berries to start a batch of berry port recently. I made sure to add nutrient and energizer, just in case.

isnt primary fermentation supposed to be open to the air ???????

Apparently, blueberries contain sorbate, so that would explain fermentation problems. Last year I made blueberry port (some elderberries) and even with K1 yeast and a yeast starter, I got only to about 14% alcohol with sugar additions before the fermentation stopped completely.

I should mention that I used a high berry:water ratio, about 7-8lbs of berries per finished gallon., so that obviously worsened the ferment conditions.

Pp

I'm new to it too, but I understood the primary fermentation was when you got the flavour and colour from the fruit.

I thought if you just used juice, as it had the colour and flavour already, putting it straight into an airlock would be the way to go.

Charlie

That's true enough. The main reson to stir a primary is to punch down a cap of fruit skins, and stir up settling pulp so it doesn't spoil before the yeast get a chance to reach them. But some air is needed early in the fermentation to let the yeast reproduce so they dominate the must. I always make a starter, so my yeast is going strong. But, stirring air in a few times early on is important as well -- the yeast will grow, and produce other things besides straight ethanol when exposed to air. That's what gives wine some of its character.