I don’t understand, how could skipping MLF result in a sweeter wine?
Usually wines that have gone through MLF can taste sweeter, because higher acidity usually keeps sweeter notes at bay - be they from fruit flavors or residual sugar. However, MLF doesn’t have any influence on the residual sugar of the wine.
Nevertheless, I myself have also wondered why in some regions they prefer to let the wines go through MLF. For example Condrieu can often be flabby to begin with - MLF doesn’t really help at all there.
Oh, did you mean that diacetyl might make the wines taste sweeter?
You really have to make a distinction between MLF and diacetyl. Diacetyl can develop during MLF, but it really is heavily dependent on the lactic acid bacteria strain, fermenting conditions, wine itself, etc. Most of MLF produce negligible - ie. undetectable - amounts of diacetyl.
If you talk about those rich, buttery and creamy wines - they are often produced specifically with a strain of LAB that purposefully produces lots of diacetyl.
Nevertheless, I myself have also wondered why in some regions they prefer to let the wines go through MLF. For example Condrieu can often be flabby to begin with - MLF doesn’t really help at all there.
I was specifically thinking about northern Rhone producers.
I didn’t know about the purposeful production of diacetyl. Ugh. That explains a lot. I was thinking that, to my palate, malic acid seems to pack a bigger punch than lactic acid, and more of it might cover up some of the stuff I don’t like.
Indeed malic acid packs bigger punch, which is why MLF is employed - instead of having that tart, incisive acidity, you get this softer and less tart acidity combined with the softer mouthfeel that comes from the higher pH.
However, malic acid doesn’t really cover up anything. The difference in flavors and aromas comes from the stuff that gets produced by lactic acid bacteria during the MLF. Plus different molecules might behave completely differently at higher pH, so there’s always that, too.
When lactic acid bacteria consume glucose, they produce acetic acid and/or diacetyl, depending on which bacterium is doing the thing. This is the key reason why a winemaker should not let off-dry wines go through MLF!
Typically LAB produce less diacetyl in warmer temperatures and in higher-pH wines.
To keep the levels of diacetyl low, the best way is to have MLF start during the alcoholic fermentation. This way the temperature is high and there should be enough nutrients for the LAB so they are not stressed and produce higher amounts of diacetyl. As long as there is enough malic acid, LAB should metabolize them into lactic acid and saccharomyces should metabolize any remaining glucose into alcohol.
During a concurrent primary fermentation + MLF, the yeast should consume most diacetyl that gets produced by the LAB.
One of the risks of concurrent fermentation is that the microbes consume the nutrients, resulting in a stuck ferment. In this case the wine might not be fully dry and/or it might retain some malic acid. This can result in bottle refermentation (and production of off aromas, depending on which microbe is fermenting what).
When doing MLF after primary fermentation, the remaining yeasts and any yeast lees can reduce the level diacetyl; if a winemaker wants to emphasize the impact of diacetyl, the best way to do this is to rack the wine off the lees before or during the MLF.
Spontaneous MLF usually results in higher diacetyl production as the winemaker can’t control which LAB perform the MLF, so the environment might favor LAB strains that are more prone to produce diacetyl.
LAB can consume also citric acid, which produces diacetyl. The more there is citric acid in the grapes, the more diacetyl gets produced during the MLF. The worst thing a winemaker can do is to acidify a wine with citric acid before MLF!
Oddly the article says that reductive environment is the best way to keep the level of diacetyl low as LAB consume citric acid more actively in an oxidative environment, but later on the article says that reductive environment encourages diacetyl production.
Furthermore, only tangentially related to the subject: it’s interesting how wines that undergo full carbonic maceration might not see any MLF at all. This is because carbonic maceration uses malic acid to produce alcohol, so typically grapes that have been fermented with carbonic maceration might have no malic acid at all after the fermentation - or the level of malic acid might be so low that MLF just doesn’t start!
However, if the wine isn’t fermented fully dry, it’s possible for the MLF to start, but if there is no malic acid to consume, the LAB might turn to metabolizing any remaining glucose instead, resulting in high levels of acetic acid - and possibly diacetyl!
That’s very interesting. I served for a number of years on a tasting panel, helping an analytical chemist identify faults and off-flavors in beers and liquors. We kept receiving samples of beer from a brewer who had facilities in a central American country and another in a Caribbean country. It was awful, with overwhelming levels of diacetyl consistently present. The breweries were attempting to make a bland, light American-style lager. We knew that the breweries had trouble keeping their environments cold enough for proper lager production (and probably had sanitation problems as well). I wonder now if perhaps Lactobacillus contamination was to blame, or at least partially so.
With lagers it’s a completely different thing. Minute amounts of diacetyl (or diacetyl precursors, like alpha-acetolactace, which breaks down to diacetyl) tends to be produced even by normal Saccharomyces yeasts - including Saccharomyces pastorianus, ie. cold-fermenting yeast used in the production of lagers and pilsners.
Anyways, it is of course possible that they have an infection, meaning that there might be some lactobacilli producing diacetyl somewhere. However, it is more likely is that they are either rushing the lagering process (not letting the yeast metabolize all the produced diacetyl), their process is too warm (which might increase diacetyl production) or they are lagering their beer after the fermentation in a lagering tank without yeast (which means there is nothing to decrease diacetyl).
A lovely showing from this lower-level Baudry Cuvee from 2005! Really quite vibrant, aromatic. Red fruits, earthy, sweet tobacco on the nose. Crunchy red currants and raspberries on the palate, medium weight, damp ground cover, sweetish tobacco and maduro leaves, short crisp finish. Probably much better like 7-8 years ago but still quite lovely. A killer vintage for this Domaine, the Grezeaux and Croix Boissee cuvées are excellent.
Chris Kissack mentioned this producer a few years ago when the thread started, but I had never had the chance to try a wine until last night:
Domaine Wilfrid Rousse - Clos de La Roche - Chinon 2010
A very enticing bouquet, with crushed cherries, peonies and strawberries, then a silky blend of wild strawberry and red cherry, a little pepper and some creamy blackberry, with a long, savoury finish. Light on its feet, but very persistent, fruity but elegant. Very youthful still, this has a long way to go.
It comes from a small 2ha plot of vines, some of which are over 100 years old.
In terms of style, I would say this is like Breton or some of Blot’s wines.
I was very impressed, it’s a delicious wine - perhaps the savoury finish makes it more like a Bourgueil than a Chinon.
I found this at auction recently for 25€, which is great value.
More recent vintages sell for 17 to 20€ depending on the vintage - so well worth looking out for.
Have had only limited experience with Loire reds (despite having visited there once). Mainly had Bourgueils, with a few Chinons. Love Cab Francs though… inspired to try some of the ones mentioned here. Thank you.
My daughter in law getting creative with the label. I liked the 2020 Baudry Grezeaux a lot. It’s pretty classic even with the warm vintage. Sure there may be a scosh of Brett, but also some dark raspberry and cassis fruit, a touch of bell pepper. 13% abv and no over ripe or cooked fruit that I noticed. I was worried I wouldn’t like the 2020s but I’m a fan based on this early look.
NOSE: a bit glou-glou at first, but with air this gives way to a clean, dark-fruited presentation with some noticeable pyrazine.
BODY: garnet-violet color of great depth; medium-light to medium bodied.
TASTE: stony; pyrazine is medium to medium+; purple-fruited — plum, mostly; some drying tannin; medium to medium+ acidity alc. not noticeable; not oaky. Ash gut impression score: 90, which is the same as mine. Stupid-good QPR at $22. This has improved since my prior bottle a year ago. Drink Now and over the near term.
Word on the street is that Clos Rougeard has left it’s US importer. I’m surprised it took this long after the Bouygues family purchased it. Curious to see where it ends up. My off-the-cuff guess is Crurated…
The wholesale price has more than doubled between the 2012 (the last pre-sale, I think) and 2017 vintages. Current W-S low for the 2017 Bourg, for example, is not far out of line with a standard retail mark-up.
