by Jeff Miller of Artisan Family of Wines (Seven Artisans, Sly Dog Cellars, Red Côte)

One of the most important decisions that a grapegrower or winemaker has to make is when to bring in the harvest.  That decision in theory is pretty much the same as when the grapes are ripe.  In practice, it’s not quite so simple.

Of course, the grapes being ripe is a pretty important aspect of the decision.  In the best of cases, the grapes are pretty much getting there right about now.  But what is “ripe”?  Ripeness is different things to different people.  There’s certainly a point where everyone would agree the grapes aren’t ripe yet, and a point where everyone would agree they are overripe.  But there’s quite a bit of time in between where opinions vary quite a bit.  I’ll return to this point in a minute.

Personally, when I’m deciding whether to harvest or not, I look primarily to the physiological ripeness of the grapes.  I take a berry sample, put the grapes in a zip lock bag, crush them, and then see what I have.  I do do a couple of pretty basic tests.  I check the Brix and the pH.  The Brix can’t be too low—ditto for the pH.  But in most years (last year being something of an exception), these parameters are rarely a big problem, at least here in California (though pH being too high, i.e., the acids are too low, is more often a problem than the Brix being too low).

Then I move on to judging the grapes themselves.  I take a look at the juice in my zip lock bag.  Is it a pale pink with a green tinge (definitely indicative of underripeness), or a dark pink, or even red (indicative of ripeness)?  I pay a lot of attention to seed color.  I want most of my seeds to be tan to brown.  Some yellow is okay.  I don’t what to see a whole lot of green (indicative of underripeness which will yield hard closed tannins).  Is the grape pulp still sticking to the seeds?  If so, the grapes are probably not ripe, though this isn’t necessarily always the case.  The grape skins can be fairly firm (not ripe yet), or soft.  In Syrah, the skins often develop a kind of dimpling when ripe, though that’s not the case with most varieties.

After I’ve looked for those things, I taste the grapes.  Are there a lot of green flavors?  If so, they aren’t ripe.  Are there a lot of cherry flavors?  That’s a pretty good indication of ripeness.  Prune or raisins?  That’s getting overripe.  Definitely time to bring them in.

Many of the flavors that develop in the wine aren’t evident in the grapes, so I don’t really expect them to taste anything like the wine.  But I definitely do not want to taste any greenness.

Now if it’s late September or October and you’ve gotten the grapes to where they are ripe, then it’s easy—go ahead and pick them.  Sometimes you need to wait a few days if the winery isn’t able to accept the grapes, but that’s usually not that big of a problem.

But suppose it’s late October and the grapes aren’t as ripe as you’d like.  You have a decision to make.  Do you bring them in or not?

This decision can be difficult depending on the weather.  If you’re looking at rain in the forecast, and you’re dealing with a variety susceptible to botrytis, then you have to decide whether to risk damaging the fruit in order to get some number of days of extra ripening.  Those days may not be that big a deal since the grapes aren’t ripening very fast in late October anyway.  Even so, we usually err on the side of leaving them hang a little longer, even if the improvement may be modest.  The converse situation can present itself earlier in the season if your grapes are already showing signs of stress and dehydration, and there’s a heat wave on the horizon.  It’s no fun to decide to wait another week or two, only to have your crop crash and burn on you.

There are other situations that can force you to make a difficult decision.  Suppose the Brix is getting high and the pH is showing a sharp decline in acidity, but the physiological factors aren’t where you want them?  I really don’t get too caught up with Brix levels, but if the pH is getting high, I really don’t want to leave the grapes out there too long for the acidity to get even lower.  True, you can add acid in the winery, but other things being equal, I’d much rather have grapes with good acidity from the get-go.

Some very mundane but important factors can force your hand.  The availability of picking crews is one.  Usually this isn’t a problem, but when it is, it’s not like you can pick without a crew.  So you may be forced to pick a little earlier or later than you’d really like.

Finally, I’m going to get back to what is “ripe”.  Some winemakers want a wine with bracing acidity and bright fruit.  I certainly fall into this category when it comes to Montepulciano.  If that’s what you want, then your definition of “ripe” is going to be earlier than a winemaker who is after opulent, rich fruit (even if there’s some prune and raisin flavors).  Those two winemakers could differ by a week or two in when the grapes are “ripe”, and the wine they will produce from the same vineyard, picked at different times, will be vastly different.

This entry was posted on Monday, October 15th, 2012 at 6:19 am and is filed under Harvest, Winemaking. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.