Yeast question

[Spanderholic]

Hi!
I'm a bit cheap, and as yeast is kind of expensive I was wondering if you guys thought this would work: use one sachet of and mix it with some sugar and water, get it bubbling away for a day or so and then divide it up into separate buckets or whatever and mix in different fruits, juice, water, simple syrup etc to make different types of wine out of the same yeast. So, verdict? I'm thinking it would work but I'm a novice :P Thanks! :)

*Edit* Totally realised how common this is, but of course that was after I put this up! Ha, ah well. Another yeast question though, what kind of alcoholic content could I predict from using general all purpose active dried yeast? Thanks :)

[Green Aura]

The wine-making bods will no doubt be able to give you chapter and verse on the subject but we only use about a largish pinch out of a sachet per gallon - I think my wine making book calls for an eighth of a teaspoon, which is much less than the contents of the sachet. We keep the sachets in old herb jars in the door of the fridge and it seems to keep just fine.

I have no idea how strong the wine is, but it's always up to the little yellow ring on the floaty thing by the time we're ready to bottle it so I'm assuming it's OK!

[MKG]

Yes, it would work. What you're describing is basically a yeast starter (some liquid, some nutrient, some acid, some sugar and a bit of yeast). The yeast gets to work on the sugar and multiplies as normal, giving you much more yeast than you started with.

If you're really into saving money, you can extend the idea. Into a litre or so (doesn't really matter much) of tepid water, dissolve a couple of ounces of sugar. Add some nutrient if you have it (if not, a smidgin of Marmite or Vegimite - and I mean a tiny smidgin - will do, and if you crush and add a quarter of a standard health-store Vit. B1 tablet, that'll be even better). Add the juice of, say, quarter of a lemon, give it all a really good shake, and then stick half a level teaspoon of yeast in. Plug the neck with cotton wool, keep it all in a fairly warm place, and wait two days (min) to a week. At that point, you can take out three quarters of the liquid and use it to start up to 5 gallons of wine. Leave the rest to settle a bit than pour it off into a jug, trying to leave any sludge behind (it doesn't matter if a bit gets through). Wash out the bottle, put the reserved yeast soup back in, add some more sugar, nutrient and acid, top up with tepid water, give the whole thing the best shake you can manage (you really do want lots of dissolved oxygen in this stuff), plug with cotton wool and repeat the process etc. etc.

Theoretically, you can keep that going for ever. However, it's best to start again from scratch now and again to ensure the yeast strain isn't weakening.

Mike

EDIT: Just spotted your addition. General purpose wine yeast, under normal conditions, will comfortably give you 13% ABV, 15% if you keep the fermenting wine at a comfortable room temperature, and 18% if you really mollycoddle it along (but I'd wait a while before you attempt the mollycoddling). That is, of course, if there's the requisite amount of sugar in there in the first place. As a rule of thumb, an Imperial gallon of wine must containing 1kg of sugar (that's natural and added sugars) will give you approximately 12% ABV. If you don't like metric, that's 5% ABV per pound of sugar.

[gregorach]

I'd just say that if you're going to propagate your own yeast, hygiene is very, very, very important. Really. I would advise making sure that you can at least make clean wine before getting into propagation.

I'll shut up now, before I start talking about storing cultures on solid media and the importance of proper aseptic lab technique...

[dave45]

For a higher %age alcohol you might try googling "turbo yeast"... should take you nearer 20%. Its optimised for bulk fermenting white sugar into rough alcohol for distilling, so I don't know what it would do to the taste of a fruit wine. (Or it may be a con and be a standard yeast with loads of nutrient, dunno)

[MKG]

No, turbo yeasts are not a con - they're designed to produce mashes ready for distillation, and the common ABV target is 22%. They do that with no problem, and some will outstrip even that, but they do it quickly and generate an awful lot of heat (so temperature control is important). They also produce a liquid which tastes like liquid manure. The result, if you want to use it without distillation, needs to be charcoal filtered - then it's rough rather than manure. Then you find some flavouring to make it taste like watered-down whisky and you're home and dry. It's all very expensive. Why not just make wine in the normal way? It's worth bearing in mind that if you get the temperature control wrong, you end up with the same alcohol-producing power as ordinary wine yeast.

Keep an eye out for "schnapps" products on the market, all at 22% ABV - that's how they were produced. And most taste crap.

Mike