I've had apple wine explosions and demi-john leakage, but to date I've never had a stuck fermentation. Last week I decided to dig up the remaining parsnips in the garden and make wine out of them.
I am following C J J Berry's recipe for parsnip wine. I've had reasonable success with wine making by following his recipes but I have to say that I haven't really tried the resulting wines in anger. Wine takes longer to mature than beer and it is better to leave the bottles alone for months. I've also had success with Hugh Morrison's method. His approach is really simple and as a result it is difficult to make mistakes. There are several bottles waiting to be tried over Christmas including mead, apple and parsnip.
Anyway, seven days later I have a parsnip must made by carefully boiling parsnips, straining them and adding sugar. Once it had all cooled down, I added yeast and nutrient. And what happens - nothing. Not a sausage. I've left the bucket of must open with a couple of cloths on top as per the recipe, but there was no activity. I thought I'd better airlock it to see if it was doing anything at all. Nothing. I added some new yeast and nutrient in case I'd killed the first lot but no luck.
A couple of days ago, I made a wine starter with yeast, sugar and some water. It started to foam. I added it to the must and nothing happened. The room is at 22 degrees - perhaps the room is too hot but yeast should live at that temperature. Modern life's problems are solved by Google and I discovered an article on the Midwest supplies website (20/1/2020 - unfortunately removed from the site). It recommends, as a last resort, making a reverse starter as follows: take some of the must, optionally add some sugar, add yeast to it and nutrient. Cover and leave it for some time. If this starts to foam, it is likely to be usable as a starter for the rest. But instead of adding it to the must, add it to a new sterilised fermentation bucket and add a small amount of the must. If this starts to ferment, then add some more - about 2.5-3 litres at a time.
I was going to do this yesterday but I got into stout earlier than expected and the IPA brew was unexpectedly tiring. I kicked off the starter this morning and it does seem to be fermenting. There is gas building up in the bin and it is beginning to come out of the airlock. I will keep adding the rest of the must over the next day or so.
Hopefully I've saved it - it would be a shame to waste the output of homegrown vegetables. I read somewhere else (and I've misplaced the link) that many of Berry's recipes are quite heavy in sugar and this apparently can cause fermentations to stick or not start.
(Added: 11/11/16 - the wine did eventually kick into life in the second fermenter. The fermenter lid was swelling and I transferred everything to a demijohn in which there is a healthy fermentation in progress. )