Reading Chromatography

This morning i removed the chromatography sheets from their jars and hung them outside the office to dry and resolve.


You can faintly see the wine spots have 'wicked' up the paper as it was carried up the paper by the solvent.


The order the organic acids resolve from bottom to top is tartaric, citric (if present), malic and then lactic. This finished sheet shows a large tartaric acid spot (yellow spots) and very faint if any malic and a small lactic acid spot. The small lactic spot could mean the wine had little malic to start with, which it did, and therefore there is little lactic produced. I like to see a better lactic spot ideally. The Wine Lab has a great pdf with instructions on the test and reading the results.

The drawback of the test is that it is qualitative, not quantitative and it can give somewhat questionable results. The test yesterday was far from conclusive, but does lead me to believe that the wines tested are vary close to being through, if not already finished with MLF.

The next step is to validate the chromatography with a enzymatic assay that give a quantitative amount of malic acid present. At that point i'd go ahead and add SO2.

I wish the test was a bit more conclusive, but such is life.

Happiness is Chromatograhphy

After the turn of the year I spend a significant amount of time checking and tracking the progress of malolactic fermentations (ML or MLF) in our new wines. This secondary fermentation is a bacterial fermentation or conversion of malic acid (think green apples) to lactic acid (think dairy acid). This conversion softens the acid profile of the wine and also supplies a degree of stability as malic acid is essentially food for a number of spoilage organisms.

Most of our wines complete 100% MLF, save our Gewürztraminer, Riesling, Pinot Gris and stainless-steel Chardonnay. We add SO2 immediately after primary fermentation to block the MLF from occuring.

When the conversion is complete we can then add SO2 to our wines for protection (SO2 is inhibitory to the bacteria that perform the fermentation).

One of the ways we track the fermentation is by using paper chromatography. This is a relatively 'old school' technique for tracking the fermentation. It uses the principles of chromatography (essentially a substances affinity for a solvent) to separate the acids present in the wine. It's a bit convoluted but it is a pretty easy method for getting a basic idea of your MLF progress.


The rack above contains 60 test tubes, each representing a single barrel of wine. They are coded with a letter and number (A1-A10 though F1-F10) so each barrel is identified. Using special chromatography paper, I 'spot' 10 wines per page with a tiny capillary tube; the smaller the spot the better. After passing over each spot three times i leave the paper to dry.



When dry I roll the paper into a tube and staple it together. The tube is then placed into a sealed container that contains a small amount of chromatography solution. I leave the paper in over night.

Tomorrow I'll take the paper out, develop it and read the results. Ill post a pic of the results tomorrow afternoon and we'll see where we stand