I suspect that this "pure organic juice" has preservatives... what do I do?

[maenad]

Farmer's market in Istanbul, I bought 6 litres of mulberry juice. The lady swore that it was pure, no preservatives, no nothing in it. BUT... there are three problems. Firstly, it does taste like just a little sugar water has been added. Secondly, there are no ingredients or labels. Thirdly - I told her that I needed to have it preservative-free in order to make wine, and she got annoyed and told me that it couldn't be used for wine, and then gave me a "bloody alcoholic foreigners!" kind of look.

I don't want to ruin the juice if it won't ferment - it's good juice. Is there a way I can test it? I'm thinking of pitching a tiny bit of yeast into a coffee cup of juice. Would that work? And if it starts smelling like a primary fermentation bucket, is that I sign that I can just go ahead?

 

[ShadesManna]

It's usually a difficult, uphill battle against preservatives - when you know what they are. Not having an ingredients list makes it a bit trickier. It could be anything.

One way to combat preservatives is to make a starter, like you mentioned. You get the starter going along merrily for a few days, making sure the fermentation is strong. Then, you add the starter to the juice (and whatever else you have in there; sugar, tannin, nutrient, acid, etc.) to give it a kick in the rump. Then, in the best case scenario, the fermentation already going from the starter overpowers the preservatives, and the yeast eats the sugars in the juice.

I tried to do this with an apple cider I didn't realize had preservatives in it until too late. It worked pretty well.

 

[bernardsmith]

If you remove a sample and pitch some yeast and it takes off then you know it's OK . I don't know that you need to wait until you can smell the ethanol but I would assume that if the juice is pure juice then the SG will be around - what? 1.045 - 1.055? and there will be enough sugar in the mulberry juice to "prove" the yeast. If after 10 or 15 minutes the yeast is not showing any activity (froth) then I would think that what you have is a problem juice. You might use bread yeast for this test rather than waste wine yeast whose lag time might be far longer...

 

[Bocochoco]

Wrong reply

 

[ehall]

does it have a label? mulberries are pretty darn sweet, what makes you think its been sweetened?

 

[maenad]

Update: yes, it was full of preservatives. I tried a few different yeasts and did them with starters, and they all died as soon as I added the juice.