June 14, 2008

Paper chromatogaphy

With most people, when they find out I like to make wine, they usually say something like, "you must really have to be a scientist." That's telling. Mention you're a chef and people seem to launch into what you cook and what they like to cook. Mention you make wine and people distance themselves and assume it's all science.

It's not true. Just as chefs don't need to be ranchers raising their own cattle, and for that matter wineries don't NEED to own and farm their own vineyards, winemakers don't need to be scientists. In fact, if I had a nickel for every time I've heard of a highly technical winemaker who's found they need to loosen up to make really great wine, well, I'd have some money.

The truth, though, is that you do need to know some wine science if you want to make good wine, just as you need to know some food science if you want to bake good bread. It's not just art. And sometimes the science can help make things cheaper and more personal. Take paper chromatography.

As I've written about my 2006 Pinot Noir, I struggled through the important malolactic fermentation, paying twice for a fairly expensive test for residual malic acid. If there's still malic in the wine, ML's not done. If ML's not done and you bottle the wine, besides the slightly sharp acid taste it might give, ML may continue in the bottle with bad results.

With my 2007, I'm doing what I see other winemakers doing, good old fashioned paper chromatography. That means getting some chromatography paper, a tall jar and a small amount of solvent similar to what you might use to develop photos. Nasty stuff to be sure, but that's part of the deal.

You can learn more about the process here, but paper chromatography basically goes like this: make spots near the bottom of the paper with your wine samples, let it dry, roll the paper in a circle and place in the tall jar. Let the paper soak up solution overnight, take out the paper and hang it up to dry. Once dry, there will be colorful spots on the paper above each wine sample, each spot suggesting the presence of a particular acid, with the intensity of acid concentration suggested by the brightness of the color.

It isn't foolproof, and it may seem a bit complicated. The solvent smell isn't great either. But for not so much money, you can do many sheets of chromatography with many wine samples per sheet. That means one set up like I've described (jar, solvent, and a 10-pack of special paper) can take care of dozens of samples, allowing you to save money and have what ends up being an easy process to stay in touch with ML progress.

Yes, there is a "simple and cheap" Accuvin test kit, but I don't find it so cheap. Maybe I'm an idiot, but other Accuvin tests, such as for SO2, just don't seem to work. And, frankly, I'm looking to learn what professional winemakers do. I know some who send everything out for ML testing, some who do that only after monitoring with chromatography, but it seems the Accuvin users are homebrewers. Could be wrong, but that's my experience. I don't mean to disparage my homebrewing brothers and sisters, but I want a different experience.

So, my barrel of 2007 Pinot Noir appears done with ML. However, my carboys of press wine are not, which means I'll stir them and bring them in the house to a warmer place than the garage to promote ML activity.

Happily, my 2007 Chardonnay and Pinot Noir Rose both show LOTS of malic acid, which I want. These aren't wine I like to go through ML, so that they're fresh and crisp like a Pippen apple, not butter and creamy and anything but refreshing. Now I'll hit them again with SO2 to further deter ML activity, fine the wines with bentonite, maybe filter if I can get equipment. Or not, since these are small lots of homebrew and don't need to be completely free from bottle sediment. Then it's bottling time for the white and pink stuff. Summer's finally here.

1 comment:

enobytes said...

Intriguing post! Good luck with bottling.