Malolactic fermentation in blueberry wine

[Tovis]

Do you have to do anything besides keep the temperature from dropping if you want to have your wine start malolactic fermentation?

 

[sour_grapes]

Do you mean other than pitching malolactic bacteria?

 

[Tovis]

Ah, so it is a bacteria you pitch to make it happen. Would this be good with blueberry wine? Also does it happen without pitching the bacteria, or do you need to add it in - or does it depend on the fruit?

 

[acorn]

In an unlikely chance that you let your wine ferment on wild yeast without killing it off with SO2 prior to fermentation, malolactic fermentation (MLF) can start on its own, without adding another yeast culture. In fact, I heard it can start on its own even in cases where you did kill off the wild yeast. The danger, however, of not following up with the addition of the dedicated malolactic bacterial culture (given that you want it to occur) is that wild MLF can pop up almost unpredictably during times you least expect it, may produce some off flavors, and can last for much longer time causing haziness and cloudiness in your wine. The worst is when it happens in a bottle.

So, if your MLF conditions are favorable (i.e. pH > 3.2, temp. > 64*F, and free SO2 is low), you can add the culture and go that path, OR, if you don't want the MLF to take place, inhibit it with lower temperatures and/or SO2 additions.

 

[Tovis]

Sounds like something I should perhaps wait a bit to experiment with.

 

[Tovis]

In this batch I did not add potassium metabisuphate in the beginning. I purchased the blueberries from a place that did a special wash to them. Might on everything from now on. How would I know this is happening?

 

[acorn]

Usually, you would see some cloudiness and a few CO2 bubbles coming out (literally just a few). But sometimes it will not be apparent. If your wine has a bite to it, then if you taste it after MLF you would feel much less of it. One way to tell if your wine has gone through any MLF or none at all is to get a chromatography paper testing kit, which will allow you to monitor the presence of lactic acid and malic acid at very least (sometimes these kits also include tartaric and citric acids for comparison purposes). However, you would generally not know the exact amount of any acid present, you could only tell if the MLF is completed, still in progress, or has not begun at all. So, if you are looking at a pre-MLF wine sample, it will have a dot on the paper representing malic acid, and nothing where lactic acid would normally be. A completed MLF wine sample, on the other hand, would usually show a large and dense dot in the lactic acid area, whereas the malic acid dot would disappear either completely, or just be a little trace of it left.

 

[SBWs]

Check out this link it covers when and when not to do MLF.

I wouldn't do MLF on Blueberry because the dominant acid in Blueberries is citric not malic. Also most fruit wines need some backsweetening and this becomes a problem once MLF starts. MLF and sorbate don't go well together. You will need sorbate to sweeten the wine later, unless you have a way to sterile filter.