It’s safe to say that rain is bad for wine-grapes.  Grape-growers fear it like I feared that big kid with anger issues in middle school.  That is why it’s been so wonderful that Australia has experienced an unexpected Monsoon season right in the middle of harvest.  The rain has been long and over-whelming, pouring heavily on us for days.  We’ve been missing work waiting on the rain and even though it finally ended Sunday, the dam in the local area is so loaded up with water it’s ruptured and today we had to be evacuated from the winery to avoid the incoming floods.  (I’d tell you more, but they didn’t tell us much in the first place, and there are no local news stations out here)

So it’s not actually raining this hard.

With all this drama over water, water and more water, I’ve been spending a lot of time thinking and reading deeper into what I know about rain. The issue with rain is very simple: it promotes rot and it promotes fruit bloating.  We’ll tackle those one at a time.

Rot.  Sounds pretty gnarly, doesn’t it?  The thing is when your apples at home go rotten, you throw them out.  However, if you are making wine in the Napa Valley and it rains, not making wine that year is not really an option, so what happens is the grapes arrive in the winery and the winemaker and the fruit begin to wage war.  Besides just being icky, the rot impacts almost every aspect of the wine- it releases a small army of enzymes that start processes the winemaker simply doesn’t want to see happen.  These enzymes negatively affect color, fruit aromas and also make the wine oxidize more easily.  The rot itself (which is really just mold) actually eats up much of the acid and the nutrients in the grape needed for yeast and to boot, it releases lots of vinegar producing microbes.  …wow, that was a long list of bad things.  This is why wine-makers hate rain, and the closer to harvest you are, the more damage it does.

They call it the Noble rot, but it’s usually not so noble…

Bloating.  No, we’re not talking about how you feel after a few too many hot-dogs.  This is pretty much exactly what it sounds like: the fruit fills up with water.  This means you lose sugar concentration as well as concentration in general.  During most of the season, growers will often intentionally with-hold water to increase concentration, so when the rain comes, it undoes a lot of the work the grower has been trying to do.

So here we are in Australia, picking up the scraps after Monsoon Season 2012.  Hopefully, we can salvage a vintage after this.  The weather after rains makes a big impact on what grows on the vine.  Unfortunately, it’s not our decision what happens from here on out, it’s just up to the weather.

*Hard-core wine nerd note- Rot does have one positive note- it promotes the metabolism of polyhydric alcohols or “sugar alcohols”, which is a terrifying name for equally scary-named glycerol, mannitol, erythritol (I’m hoping I never have to pronounce that one out loud), arabitol, sorbitol, xylitol and myo-inositol.  Although mannitol has a little of a bad rap, generally, these compounds (especially glycerol) are purported to provide a soft sweetness with a round-ness on the palate and fuller mouth-feel.

*Personal note- did anyone understand the hard-core wine nerd note?