6 replies to this topic

[jmusser]

I started MLF on November 3, 2008 on this years Norton. I am using Eno Beta. I ordered Accuvin test kits for Malic acid and Lactic acid. I tested the wine yesterday to see where the process was. (It is still visibly producing the smallish bubbles and doing the snap crackle pop) I have read that Norton has very large amounts of Malic acid in it as compared to other varietals. I got the following results. The amount of Lactic acid is > 400 mg/L while the Malic acid is still > 500mg/L. The literature that came with the test kits say to continue MLF until the Malic levels < 30 mg/L. Do these numbers seem reasonable to those of you with experience in measuring MLF progress? Thanks in advance for your advice.

[D&S]

I started MLF on November 3, 2008 on this years Norton. I am using Eno Beta. I ordered Accuvin test kits for Malic acid and Lactic acid. I tested the wine yesterday to see where the process was. (It is still visibly producing the smallish bubbles and doing the snap crackle pop) I have read that Norton has very large amounts of Malic acid in it as compared to other varietals. I got the following results. The amount of Lactic acid is > 400 mg/L while the Malic acid is still > 500mg/L. The literature that came with the test kits say to continue MLF until the Malic levels < 30 mg/L. Do these numbers seem reasonable to those of you with experience in measuring MLF progress? Thanks in advance for your advice.

I don't measure lactic acid but some will be present as a result of alcohol fermentation by yeast. Prior to the start of MLF, a level of malate >500mg/L is also normal for many wines.

I've never worked with Norton, but it appears that your ML never really got off the ground. Is your wine within the normal range to promote MLF with respect to SO2, pH, alcohol and temperature? If not, consider making adjustments. Did you add an ML nutrient at inoculation? This may also help. Finally, you may consider reinoculating with a fresh ML culture. < 30 mg/L is often the benchmark used to considered MLF complete.

[jmusser]

D&S, thanks for you response, but I do think the MLF has started---I should have also put my other relevant readings in the post. I believe that my readings are well within the recommendations that I have read.

My pH reading prior to MLF was 3.26, the temperature has stayed right at 70-2 F, SG was 1.002 at the start of MLF, I tested the SO2 to be down to 15 ppm at the start, and had used the ML nutrient (I believe it was Acti-ML according to the dosage recommendations). As I mentioned, I believe the MLF is currently going on, but I was curious about how accurate the Accuvin test kits were.

[Doyle]

There are only 5 color gradations on the accuvin chart. Starting at white which is 0 and progressing to 30,75,160 and >500. Anything in between is done by interpretation. It is generally accepted that MLF is complete when Malic is below 30 ppm. If you want high accuracy in your Malic measurements, you pretty much have to go to a Lab. Chromatography cannot distinguish levels below 100 ppm. Accuvin has the ability to tell you when the level is down at 30 ppm or lower and that is mainly what you are interested in. Some grapes have a lot more Malic in them but as long as there is Malic present, the bacteria just keep eating the Malic and converting it to Lactic so completion with a high Malic grape is no different than a low Malic grape, you just have more Lactic acid at the end.

..Doyle

[jmusser]

Doyle,

Thanks for your feedback. Do you happen to know if grapes (Norton or any others) have any Lactic acid in them initially? I got a reading of >400mg/L when I did my first Malic test. Accuvin also has this test and I thought it would be interesting to see how much of this was being produced. My only problem was that I did not have the test materials when I started the MLF back on the 3rd of November. I just tested the other day when the bubbling really slowed down.

[mokadir]

If I recall, there should be little, if any, measurable lactic prior to fermentation.

Check out this link http://www.grapestom.../wineacids.html

[jmusser]

Thanks for the link, it gave me the info I was looking for. I guess I will just wait and see if my Malic acid starts getting down to a range that the Accuvin test will register. Last year I think I waited too long on the MLF and got a little of the rubber smell going on. I want to get my so2 levels up and avoid that potential problem this year so I am trying to do a better job monitoring progress. Every year I seem to learn more about the process. I started with kits in 2004 and planted my small vineyard that same year and now for the last three years we have been getting grapes----the process is sure much more interesting than working with kits, but I still like to make a kit on occasion.