I had some turbo yeast left over, and figured I'd try make a couple litres of ginger beer (sugar, grated ginger, a little lime juice) and elderflower wine (sugar, elderflowers, lemon juice and zest) with it. Both have ended up with the same extremely unpleasant bitter flavour. They're currently undrinkable. Is there anything I can do to get rid of it? Currently I'm aging the elderflower wine and hoping for the best; I started the ginger beer later and that's still fermenting.
IMHO using turbo yeast for fermenting beer or other fizzy/alcoholic drinks is "less than optimal". It is not a yeast meant for directly fermenting drinks - it is a yeast mix meant for producing high alcohol content in a short time. The mix contains yeast and a lot of nutrient which can impart a biter flavour if not used up during fermentation. The idea of this yeast mix is to produce 24L of 20% alcohol mash for distillation (or to drink only if one has run out of methylated spirit :)
It may be advantageous to go buy some "normal" brewing yeast or, if all else fails, use bakers yeast. It is quite adequate for making ginger ale.