Malolactic Bacteria

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Malolactic Bacteria

Postby Witch Doctor Dale » Mon Apr 20, 2009 6:01 pm

I have a batch of cider made from crab apples. Way to sour to drink. If I use this bacteria to lessen the sour taste, what do I do? Put the cider in a CO2 purged carboy, add the bacteria, how long till I can bottle? Does this produce any gases?
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Postby BeerGuy » Mon Apr 20, 2009 6:15 pm

I've been curious about ML fermentations. I hope somebody can enlighten us.
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Postby karst » Mon Apr 20, 2009 7:56 pm

Dale

I have been reading up on MLF and Jon Iverson devotes an entire chapter to it in his book Home Winemaking Step by Step

You likely have one or more conditions adverse to using Malolactic bacteria. They are known to be finicky. High Alcohol, High Sulfite, Low Temperatures and Low pH are the main adverse donditions. These bacteria might tolerate one of these but not two or three. You could adjust temperature (75-80F and proper acidity and pH (). Doubt if you have any free SO2 to contend with. Do you have a high ABV? It is somewhat difficult to get MLF started after fermentation is complete and MLF is usuallly began about two days after the yeast starter was added.

MLF is not easily induced in white wines and benefit from warmer fermentation and having grape skins present. Your finished cider would seem more like a white wine to me.

Another problem will be the increased diacetyl from the bacteria and by waiting you have taken away the chance that your fermenting yeast will consume most of it.

Now that you have racked off the yeast lees (important source of nutrient for the bacteria) you will have to supply yeast extract or a malolactic nutrient. I have Fermaid 2133 that may help here ( although yeast love DAP malolactic bacteria are indifferent to it!).

Lastly if you are not able to determine when MLF is complete and quickly lower temperature you will likely create undesirable side reactions giving off flavors and aroma. If MLF is incomplete and restarts after bottling it can completely remove all you acidity. You can treat using 1 gram of lysozyme per gallon to kill your ML bacteria. This works by disolving the cell walls of gram-positive bacteria.

Vinters reduce the risk of acetobacter by adding a tablespoon of brandy or better spray a mist of Everclear over the surface. Also, you need to protect against oxidation and contamination. A blanket of CO2 or argonne is useful

Paper chromatography is the best way of testing for completion of MLF. But in your case almost all the acid maybe malic and you can stop when you like the taste or by doing titrations for direct measurement (assuming you actually get MLF started!).

My source list 5 different strains of cultured ML bacteria, some producing more diacetyl, some working at lower pH and some at lower temps.

You may want to consider using the Oregon State University strain that works ass low as 2.9pH. It is marketed by Lallemand as "OSU" and by Wyeast labs as Vintner's Choice". Vinquiry also markets it in 2-gram packets as "MCW"

MLF will generate tiny bubbles of CO2 which are sometimes used to detect malolactic activity. This assumes your usual fermentables are not present and you wine (cider) is bone dry.

You can bottle after MLF is complete or when you have stopped MLF.
Expect some overall loss of fruitness.

That's about it. May want to check with the pro's and let them know exactly what your trying to do. Be sure to get a good pH reading and they will also want to know you est. ABV %. Let me know if I can help with the fermaid 2133 nutrient.

Larry W
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Postby Witch Doctor Dale » Tue Apr 21, 2009 4:19 pm

Good information Larry, but how to implement????
I have a case of cider that is basically undrinkable, was reading various cider making websites and the talk there goes that the cider is put in barrels to ferment (traditional method), overwinters outdoors, the yeast that enjoy cool ferment out the sugar do there thing, then in early summer when it warms up the MLF begins, and after you have the perfect cider. Mine is too acidic and while I added cider yeast (White Labs), I did not sterlize the juice in any way. I figure (hope) that the bacteria were not present and by adding some, I could make this drinkable. So if I pour the bottles in a purged (with CO2) carboy and add this, should I wait to bottle till it taste good, or can I prime, bottle right away, and then deep chill when it taste good. If I deep chill, am I killing the bacteria or when the cider warms, will it kick right back in?
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Postby HarvInSTL » Tue Apr 21, 2009 5:28 pm

Larry,

I'm going to have to disagree with you on the following points.

It is somewhat difficult to get MLF started after fermentation is complete and MLF is usually began about two days after the yeast starter was added.


Quite the opposite. MLF isn't hard to start after the fermentation has complete. Both my Merlot and Cabernet Sauvignon weren't inoculated until well after 3 months had went by.

The second most significant acid in wine is malic acid, which is found in apples.

What needs to be determined is if Dale's cider has malic acid or acetic acid. If it is the later, no amount of MLF will help.

If the acetic acid is caused by acetobacter your real only option is to sulfite, bottle and drink as soon as you can. There is no magical chemical or process to remove acetic acid.

Malic acid has a green apple sensation, while acetic acid has a familiar sour taste and smells of vinegar.

If you want to test for malic and/or lactic acid you will need to either do a paper chromatography test or use one of the quick tests from Accuvin.

The decrease malic acid you really only have 3 options. (Well you can add water as a fourth option, but never one I would recommend)

1.) Blending (Use the Pearson square to determine the proper blend ratio)
2.) Acidex or Sihadex (Chemicals used to reduce malic acid)
3.) MLF

MLF is not easily induced in white wines and benefit from warmer fermentation and having grape skins present.


MLF is easily induced in any wine as long as the following is taken into consideration.

1.) Temp - Higher than 64deg (Below 64deg makes for a difficult to very difficult MLF environment)
2.) Free SO2 - Less than 5mg/L (Anything between 5-10mg/L makes for a difficult MLF environment, and anything above 12mg/L is down right almost impossible)
3.) pH - Greater than 3.2 (Less than 3.2 makes for a difficult to very difficult environment for MLF)
4.) Alcohol - Less than 13% (I wouldn't attempt MLF on anything above 15%)

As well since MLF is normally done after maceration (even in white wines such as Chardonnay), there would be no grape skins in contact with the wine.

One thing I didn't see pointed out is that if you do a MLF, do not stabilize with potassium sorbate. Unless you like the geranium odor that results in the potassium sorbates reaction with the lactic acid.

As far as nutrients for the MLF go, you could always use Opti’Malo Plus
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Postby karst » Tue Apr 21, 2009 9:52 pm

Dale (Anthony)

I figured that Dale has ruled out acetic acid/acetobacter (in which case its a drain pour)

I have no information re Acidex or Sihadex (Chemicals used to reduce malic acid) nor have I read about the Opti’Malo Plus nutrient.

I can confirm the geranium problem Anthony raises.

I am glad his MLF was easy (both Merlot and Cabernet grapes are reds and I would expect crabapples to behave differently prehaps more like a white grape?)

Do the pro's on the cider website have much experience with doing this? I could see you blending your bottles with another young cider after MLF had began - with some active fermentation going on you would have the CO2 blanket going for you.

If Anthony's MLF is still active you could blend a bottle of your cider with some wine and see how that behaves. Perhaps start with some apple juice and pitch yeast followed by ML bacteria and start blending your bottled cider. I can donate my winemaking book (it came highly reccommended by Jack Keller and some others - almost all of my information was word for word or paraphrased from author Joh Iverson -a skilled winemaker of over 20 years) and I also offer the use of my pH meter and calibration solutions.

Anthony which MF bacteria strain did you use in the Merlot/Cab?

sending both of you some detailed MLF info by email. If others are interested send me a PM request.
"Once the thought arises, the word is spoken and the deed is done, the thought, word and deed will live on and impact others long after we have ceased thinking, speaking, doing.
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