Some people get grossed out by the idea of eating or drinking fungus. I, myself, am a massive hypocrite. I won’t eat mushrooms. I’d absolutely love to love them, given how nuts people go over them, but I just can’t cope with the texture and the knowledge that it’s a fungus. Blue cheese? Not a worry. Sweet wines made from fungal infected grapes? Amazing. You’d think I’d just get over myself, right?
When producers are making a sweet wine they’re looking to make sure there is residual sugar left in the wine after the fermentation is over. A couple of ways to do it, either stop the yeast fermenting before it’s used up all the sugar, or make sure there’s more sugar in there than the yeast can handle.
The method of allowing the grapes on the vine to be infected by the noble rot fungus (botrytis) does the second. The fungus splits the grape skins, and the water in the grapes evaporates. The grape that’s left is a shrunken, highly concentrated bundle of flavour and sugary goodness! When pressed, the botrytis adds it’s own flavours of marmalade and honey, which is pretty bloody nice.
There are a couple of issues with this method. Firstly the rot affects the grapes at different rates, so the pickers need to do it by hand and make quite a few passes through the vineyard. This makes it fairly punchy to produce, so it’s not usually all that cheap in the shops.
The other problem is that it’s not guaranteed that the rot will set in. In this case producers usually just let the grapes sit on the vine to raisin. You get the concentrated grapes, but not the additional (and highly prized) botrytis flavours. Still really nice though.
Don’t fear the fungus!
Other posts in NWTW Week 20
From the Scottish online grocery shop; Gardiners of Scotland