I don't think you'll get far with any of the above. Of the 3 options the wild yeasts on the skins are the only possibility but you'll be lucky if there is enough to do the job. Bread yeast is a different strain so no good, and you need the right amount so pouring some random liquid in would not be a good idea, never mind the effect of the elderflower on the final product.
If I were you I'd just wait and get some of the proper stuff so you don't end up wasting your crop. Good luck!
Wild yeast will do fine, if a little slow starting. We let a couple of batches go every year at work.
The yeast in the elderflower will probably be all dead by now.
Saccharomyces cerevisiae is the same yeast used in bread & wine, so it will do the trick. A wild ferment starts with other strains, but only Saccharomyces cerevisiae can tolerate alcohol over about 5%.
Vinegar is usually a caused by a lack in cleanliness or not keeping your vessels full & sealed after ferment.
Well, for the benefit of anyone trying the same thing…
The natural yeast got going pretty quickly and was happily fizzing away, but the smell was not right at all. Possibly there was nothing wrong – I don’t know – but not wanting to end up with 20 litres of chain degreaser I chucked in some campden tablets, which slowed it down a bit.
Some packets of yeast arrived on Tuesday, so I put one of those in. It now smells a lot more sensible. A sort of yeasty, slightly alcoholic grapey smell.
I chucked in some more grapes that I found on the vine, which is why it looks like alien brains.
Erm? You probably should have tried to squeeze all the juice out of the grapes before ferment. Leaving the juice to settle overnight would leave nice clear juice on top.
But anyway, it should be alright if a little bitter.
I’d go easy on the camped tablets at this stage as well, you could kill the yeast.
Yes, it is isn’t it. I guess I should have put some random chemicals to clear it, although I would have thought it ought to clear somewhat anyway. The elderflower certainly did.