Science meets art

Paper chromatography results
Gosh, what’s the correct answer? Find out after the fold!

If you guessed paper chromatography results, you really should get out more… but you’re also correct. It’s a test I did of four wines currently in our stable to see if they’d finished malolactic fermentation yet. Knowing they’re done with malo means it’s safe(r) to bottle, since you know that the wine can’t willfully launch into secondary fermentation under cork, producing unintended sparkling wine at best, and explosive results at worst.

In a nutshell, paper chromatography measures, by a kind of color signature, the presence of something in a solution (in this case, acid in wine). You put tiny dots of the wine along a line near the bottom of the paper, then stick that paper in a solvent, which, as it seeps up the paper, pushes the acids different distances up the sheet, depending on what they are. Once you pull it out and let it dry (or “develop” it, as we chromatographers like to say, nudging our horn-rims further up our beaks), the solvent and acids dry as different colors.

For our test, I dribbled spots of four wines on the right, but as benchmarks, drops of four different acids on the left as well: tartaric, citric, malic, and lactic acids. Since malolactic fermentation is the process of converting sharp malic acid into rounder and more complex lactic acid, you can tell whether that transformation has completed by comparing the lactic and malic spots to your own samples.

So in our case, you can see that malic (the M) spot crept midway up the paper, while the lactic (L) spot has no fear of heights and scrambled nearly to the top. Now check out the wine spots: the ’06 Peugeot (the left-most in the bank of four on the right) shows two spots above it, one more or less on a line with the tartaric spot (all wines would have this spot), and then one that climbed as high as the lactic spot. Conclusion: malic has been fully converted to lactic, and malolactic fermentation is through.

Moving right, the next dot is the rosé we’ve got cooking. Note that, scandalously, it has three spots — two at the same level as the Peugeot, but one in-between, not-too-coincidentally at the same height as the lactic dot. So there’s still some lactic in the wine, which means our rosé has more malolactic fermentation joy ahead of it, if it’s even started at all. Sadly, my dreams of sucking down this lovely rosé on Valentine’s Day will have to wait.

Lastly, the two spots on the far right are George’s “Le Plancher” (aka Floor) Pinot, and the Emerson Pinot. Both appear done with malolactic as well, and therefore safe to bottle.


2 Comments so far

  1. sam January 29th, 2008 9:37 am

    Amazing stuff. It’s art and science.

    I think we could put up a gallery of wine chromatography results.

    Thanks for your attention to all this and for producing these wonderful descriptions.


  2. Les Blog » 2007 Chromo results July 20th, 2008 12:18 pm

    […] in hand, I put all four wines through paper chromotography yesterday (for more background, see here). The aurora borealitic results are […]

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