green scum (mould?) on sloe wine

[JoseyJo]

I have a demijohn of sloe wine which has been fermenting for about 2 months. For about the last month it has had a ring of green scum/mould around the top - it doesn't seem to be getting any worse. Is this something to worry about? Is it mould or just some green "stuff" from the sloes? It actually looks like the sort of green algae that grows around the top of water in containers outside Would wine grow mould while it was fermenting? I was going to rack it tonight & hope it isn't ruined....
Thanks, Jo

[MKG]

I've never seen such a thing, but I'd stick out my neck and say it's nothing to worry about. You can get mould growth (not necessarily harmful) on the surface of a wine, but it's far from common. Sticking my neck out again, I'd say that it's most likely to be yeast which has been stained by some colouring matter originating in the sloes or simply stray bits of fruit debris.

As always, use your nose as a guide. Does it smell OK? It may smell unpleasant - a strong whiff of heavily-scented carbon dioxide isn't nice - but you're looking for a bad egg/rotting cabbage/general rot kind of smell. If you don't get that, then strain off a little of the wine and taste a sip. Again, it probably won't be too pleasant at the moment, but I'm presuming that you know the astringent taste of sloes and so will recognise anything which shouldn't be there (that astringency disappears with maturation). You may even like the taste - in which case there isn't a cat in hell's chance that there's anything wrong.

If there is anything untoward, even if you're not too familiar with the smells and tastes, you will know - either the smell or the taste will make sterling efforts to make you feel sick. If you don't get that, then carry on with your racking, doing your best to avoid transferring the culprit - but I'd recommend one Campden tablet per gallon to be on the safe side.

Let's see - if I had to bet, I'd be better than 90% certain that there's nothing wrong.

Mike

[JoseyJo]

Thanks. It smelled fine so I've racked it and it's fermenting away again. I've never used campden tablets so far, as I've preferred to add as little as possible to my wine, but maybe I'll get some to add this time. Can you add them at any time? I've only got half a demijohn of wine now as there was so much sediment, so will a whole tablet be too much do you think?
The wine did taste very astringent. I'm never sure whether/when to add more sugar (wine-making novice...) but as it is fermenting well at the moment perhaps I should leave it alone. The sloe wine is a bit of an experiment - I defrosted the sloes to make gin but didn't buy any gin in time so decided on wine rather than waste them. Is it usually a nice wine?
Thanks again.

[Green Aura]

If it's still fermenting can't you just top it up to make a full demijohn again and maybe add a little more sugar. Otherwise it might be too strong, too tart and oxidised?

[MKG]

Don't add Campden tablets AT ALL if it's still fermenting.

A couple of things you've said make me think GA may have the best advice for you, JoseyJo.

Give us the basic recipe you used (weight of sloes, amount of added sugar, how you prepared the sloes) and we'll be better able to give you advice.

Sloe wine can be gorgeous, but the time you have to allow it to mature depends upon how many sloes you used to make it and how sweet you want your finished wine to be.

Mike

[JoseyJo]

Oh dear... this is where I learn I should write things down... I don't remember the exact recipe, I found ideas of quantities on the internet. I think I used equal weight of sloes/sugar (around 2lb each I THINK) plus some sultanas. The sloes had been frozen so were already pretty mushy, so I just added hot/boiled water to fruit (up to about 1.5l mark) and added sugar - allowed to cool then added yeast. Left for 10 days or so stirring once a day. The result filled a 1 gallon demijohn almost to the neck. There was so much sediment that after racking there is now half a demijohn. Generally I like fruit wine sweet (well I certainly liked the plum wine I made when it was quite sweet and syruppy rather than the following year's rather dryer taste.)
Don't know if that's enough info to help anyone!! I will make a resolution... next time I make wine I will WRITE IT DOWN!!

[MKG]

That's OK - there's plenty of information there. If you added 2 lbs of sugar, then you can expect a wine of about 10% ABV - per GALLON!!!! as opposed to a half-gallon. Plus a little bit from the sugar in the sultanas, but if that was only SOME as opposed to a pound or so (the usual amount would be about 8 ozs), it can be safely ignored. For a sloe wine, I think 10% might be a bit on the low side.

OK - you're a little light on the sloes, so to increase the amount of wine to a whole gallon, you need to add a little more flavour. Grab yourself another pound of sultanas (or raisins), chop 'em up and then boil them for ten minutes in a pint of water. Allow that to cool. That'll provide a bit more flavour, a bit more body, and a bit more sugar - at least a half-pound of sugar, in fact, which will take your final alcohol content to about 12.5% - much better!! That additional sugar is from the sultanas, by the way - don't go adding sultanas PLUS sugar.

When cool, strain the lot through a bit of muslin or a tea-towel (or anything else which is similar and grabs your fancy). Make sure you give the whole thing a bit of a squeeze to extract as much as possible (but don't go too mad), then add the juice to your demijohn. Top the whole thing up with tepid tapwater (leave it in the kitchen for a couple of hours to take the chill off) to about three-quarters of an inch below the bottom of the airlock, put the airlock back in and leave the demijohn in a warmish place to ferment to a finish. It'll look muddy for a while, but that's OK.

When it really has finished (ie there are no more bubbles and the liquid has cleared and you can see a deposit at the bottom) rack it into a clean demijohn. This is the point at which you can use a Campden tablet, but you don't have to if you are gentle - don't splash the stuff around too much.

Taste it at this point and decide if it needs to be sweetened. If it does, leave it well alone in the same warmish place for a month or so, keeping your eyes on it - it might just decide to have another go at a bit more fermentation. After the month (assuming no further activity) rack it again. Make a sugar syrup (say, four ounces of sugar in as little hot water as will dissolve it) and add this to the wine. Replace the airlock and watch it again for a short while - two days should be plenty, and you're hoping that fermentation will not restart. If all's well, taste it again, than add more sugar syrup if it's needed or sit back and get royally drunk.

The easy alternative is to do everything up to the point of sweetening, let the wine finish completely, than add sugar syrup to sweeten it just before you drink it.

Enjoy ... Mike

[JoseyJo]

That's great, thanks! I guess I could pick more sloes (or use some more of the ones put aside for gin in the freezer) and make up another small batch to add?

Re the sweetening, I might try adding some sugar syrup to my too dry plum wine...