here is a repost from anotehr thread
Zen and the Art of Malolactic Fermentation ( a how to guide)
Malolactic fermentation seems to cause no end of fear and anxiety in homewinemakers , judging by the posts I’ve read this forum in particular is infected with this irrational fear .
Without going too deep into the science , I will attempt to explain the fundamentals of malo lactic fermentation or MLF.
Grapes contain 3 main types of acid , tartaric , malic and citric.
Typically 80% , 19.5% and .5% (not exact just to give you an idea of the typical proportions , the level varies)
In broad terms the riper the grape the less acid it contains , and the riper the grape the lower the percentage of malic makes up of the total acidity.
Malic acid is the sharpest acid , and in a red wine its undesirable . you’ve got enough mouth puckering sharpness from the tannins.
Malic acid may be converted to lactic acid by inoculating the wine with a live malolactic bacteria culture (MLB)
What the MLB does is convert the malic acid to lactic acid and carbon dioxide. This is known as Malolactic fermentation or MLF. (strictly speaking its not a fermentation but a enzymatic decarbolisation, but who cares ? its MLF to us winemakers)
By metabolizing the malic acid the wine is made softer to taste , has better body and more complexity.
The total acidity will drop too and the ph will rise, how much depends on what the levels were to start with.
All non kit red wines should go through mlf . Why ?
Well the reason above is important enough (listening juice pail people?)
but there is a more important reason. With red wines you ferment them on the skins , skins contain all sorts of wild fauna on the skins , macerating the juice and skins together increases the likely hood of wild mlf occurring or lactic acid bacteria spoilage. (ever had a wine turn thick or grow strings in it and taste bad? That’s lab (lactic acid bacteria).
Wild mlf and lab bacteria are related to the friendly malolactic bacteria we us but they produce off flavours and other types of spoilage.
But what if I use so2 at crush and so2 before bottleing?
Yes using so2 at crush and bottleing is a best practice as these will reduce the likelyhood of wild mlf or lab but free so2 levels drop over time as the wine ages leaving little or not protection . You might have bottled your best red ever , then when the free so2 level drops these wild bacteria can come alive and if the wine is still full of malic acid (their favorite food) they can bloom and make you wine go fizzy in the bottle (the number one amateur flaw I see at competitions) or thick like snot.
So conducting mlf is about getting rid of malic acid so these potential spoilage bugs would have nothing to eat when your so2 level drops and won’t spoil your wine.
So the best wine you ever made that tasted great at bottleing will still taste great 6 months, 3 years, 5 years after bottleing.
You’ve made a wine that is biologically stable and free of bacteria food so it will age well.
Got it?
Anything scary yet?
Ok , there are a few strategies for successful mlf .
First off , is your ph above 3.2 and your alcohol level under 15% , if not you should adjust these before you even start primary yeast fermentation.
(fyi , primary fermentation is the alcoholic yeast fermentation , secondary fermentation is a restarted yeast ferment by the reintroduction of sugar , ie champagne or amarone. This is malolactic fermentation or mlf, never , never , never , never , never call MLF secondary fermentation. Use the right vocabulary or forever be confused. Also to avoid confusion , professional winemakers call them carboys, tanks, vessels, barrels but never never never a secondary fermenter a secondary fermenter is only used for charmat process sparkling wine
http://www.bortolomiol.com/en-UK/the-charmat-method.php . Again get this right to avoid confusion)
There are options for when and how to inoculate and each of those choices have pro’s and cons and risks.
I am going to explain the lowest risk most reliable approach that has worked for me without a single failure.
First off , liquid cultures are very unreliable , they don’t like it too hot or too cold and hate shipping and have a short shelf life. Not using them will reduce your headaches a lot. In a professional environment fine but mail order or LHBS retail sales, forget it.
Select a dry culture , morewine sells a wide variety . the cheapest one vinflora is fine , I used it for 10 years without issue, but the newer ones are better adapted to difficult environments and are a few weeks faster. Vp41 is a good one as its very tolerant of high temps and so2. Vp31 is good for very low ph wines (hybrids & American grapes )
Some MLB produce higher levels of diacetyl , all you need to know about that is if you are doing a mlf on a chardonnay and want that buttery flavor , pick one that produces diacetyl (beta is one) . For red wines it doesn’t matter unless you are working with hybrid or American grapes with acid levels over 11g/l , in that case pick one that doesn’t produce diacetyl VP41 is one.
But for all other reds it doesn’t matter , it will not produce enough of it that you can taste it.
I debated leaving that out , but you have the info , relax and don’t worry about it.
So you have your culture .
To increase its chance of success , you may add 50g of acti ml to 250 ml of water (distilled or bottled , no cholrine) stir well , get the actiml well mixed in.
Then add your 2.5 g culture of dried mlb to the mix. Stir it in gently a few times over the next 15 minutes.
You may then add it to your wine .
Or to increase its chance of success (optional) you may build up your culture.
Relax its easy.
Add 250 ml of preservative free (no sorbate or sulfites) apple juice to your 250 ml culture.
use a one gallon carboy to hold my culture .
put a airlock on it and slosh it around gently to mix the apple juice with the culture.
Then leave it in a warm spot over night , not too hot or too cold. I use the cupboard that contains my hot water tank and set it on the shelf above my tank.
12 – 18 hours later take a measureing cup and mix 250 ml bottled water with 250 ml of the wine.
Add it to your culture
Put the airlock on Slosh it around a bit and place back in the warm spot for 24 hours.
24 hours later I fill up the one gallon carboy half way with wine, you could fill it up all the way if you want (good idea if you have lots of vessels to inoculate , one 2.5 gram sachet is good for up to 250 litres , if you have more than that you can add more 2.5 gram sachets of the same mlb but still only grow a 1 gallon culture it will just be more dense with bacteria.)
3 days later , you should be seeing all kinds of bubbly activity .
At the stage the main wine has already been pressed , settled and racked off the gross lees (the sludge that settles in the first 24-48 hours after pressing.) and is in carboys , tanks or barrels sitting on its fine lees. The wine should be in a warm location ,68’F or 20’C (normal room temperature) for a couple days to warm up before inoculating.
add 1 g per gallon acti ml or optimalo nutrient to the wine and gently stir it in and make sure the fine lees are stired into suspension and the added nutrient (optimal or actiml) is well distributed.
The lees and nutrient make a welcoming environment for the mlb.
Now gently stir your 1 gallon culture and add it to your main wine.
When the wine is in multiple carboys or tanks , I use a 100 ml syringe to divide the culture between all the carboys and tanks . makes life easier (faced with 25 carboys it’s the best way).
Gently stir your carboy after the mlb is added (avoid too much air) and replace airlock.
Keep the room warm, 68’F or 20’C , it’s a good idea to have something under the tanks or carboys to insulate the carboy from the floor , I use some carpet underlay left over from the basement renovation.
One a week for the next 6 to 8 weeks gently stir the lees back into suspension.
At the 6 week mark , use paper chromatography to see if your mlf is done.
(this test is very easy , just follow the instructions in the kit)
If its not done , add a ½ g per gallon actiml or optimalo , stir it up and let it go a couple more weeks.
Test again at 8 weeks, if its still not done, post on the forum.
its not as hard as it seems , your wine will taste better and be at less risk of spoilage.
don't forget to add your so2 when mlf is complete.
