no added sugar...

I wonder why I see fermentation stop dead when there is still sweetness left in these new no-sugar-added fruit juice cartons. I wonder if my yeast can only handle glucose but not the fructose?

My technique is sacrilegious in every way, but it works fine with off the shelf pasteurized corn syrup or sugar boosted fruit drinks! I long ago abandoned wine yeasts and bubble traps, and simply shove some cheap bread yeast into a fresh half gallon plastic container of supermarket juice. In hours it bulges and I refrigerate, then use. Man, especially the cranberry ones are just super good... evolving from a bubbly to an alky drink as it is drained down.

But these newer unsweetened juices (with no artificial sweeteners either) bulge but don't generate or regenerate bubbles or alcohol. It gets to the bulging state fast enough, then goes dormant somehow and only has the barest trace of bubbles or alcohol. The strange thing is the juice is still sweet, so appears to be ready to feed the yeast (just fructose?).

The fact that my mega jar of yeast expired in 2011 should have little bearing because it works fine with factory-sweetened drinks (it has lived in a freezer). I hate to add sugar or go to an expensive yeast without knowing one of those is plainly needed... suggestions? Added sugar may negate the clean pasteurized state anyway.

daft said:

I wonder why I see fermentation stop dead when there is still sweetness left in these new no-sugar-added fruit juice cartons.

Click to expand...

Alright I solved my problem, but it tends to bring the product into the realm of soda rather than cider. What I do now is interrupt the fermentation process early... when the (factory) fruit juice container just gets hard rather than grossly inflated and distorted. So there is little taste of alcohol, yeast, or driven-in bubbles. But there is ongoing foamy bubbling and tart complexity of taste that is great... I used Welches unsweetened concord grape which has never turned out so good.

I tried the same approach with a highly sweetened but otherwise pure lemonade. I didn't trust pressuring up the large (Sams Club) container, so just added the yeast and recapped for about 4 hours on the table, then a couple hours in the fridge. This one did get alcoholic, and the yeast raged on even after a dozen pourings. Used some of the foamy stuff over breakfast cereal, and poured other into an applesauce container which made a delicious fermented soup.

I guess my earlier approach of building up a lot of pressure before first venting was sometimes killing the yeast. I will continue discussing in the soda section because it ferments so little this way.

Are you remembering to check for preservatives in the juice?

I did a similar experiment recently with Indian Summer cider. (No preservatives, no added sugar) I split 1 gallon into 12 oz beer bottles, added 1/8 tsp champagne, then capped, and cold crashed one every 12 hours. On opening each one, anything past 24 hours became a gusher, and anything past 72 had noticeable alcohol flavors.

So I'd look for other culprits. Because fructose vs glucose, yeast don't care.