Questions about malolactic fermentation.

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Paul Gordon

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Howdy folks.

I created a wine from an old grape vine in my garden around two months ago, this was my first attempt at making wine and was a very fun time, I did not perform a malolactic fermentation post the primary fermentation.

The wine is very tart, it has a strong alcohol flavour behind an extremely acidic taste, so am I right in assuming that this isn't the result of some acetobacteria turning the ethanol into acetic acid? Could the tart flavour be a consequence of a lack of malolactic fermentation?

Would it be possible to induce a very late stage malolactic fermentation? Could the impurities be removed in another fashion (maybe freezing out the impurities)?

How would one go about isolating the correct bacteria to inoculate the wine? Would any lactobacillus be a viable choice?

Thank you for any help provided, I understand that this, being my first ever wine batch (30 litres!), is most likely to fail but I am interested in trying to remedy the problems and do it right next time.

p.s. How do small home brewers induce malolactic fermentation in their batches???
 
Doesn't sound like you failed at all. Sounds like you have a young wine that hasn't gone through MLF. Others will chime in but most here acquire their MLB from local brew supplies or online from sites like morewine.com, etc. I used VP41 this harvest.

What type of grapes/wine red or white?

Have you hit the wine with Potassium Metabisulfite(Kmeta) or campden tablets yet? If not you'll have a better chance of getting MLF to kick off.

Good luck and welcome.
 
Doesn't sound like you failed at all. Sounds like you have a young wine that hasn't gone through MLF. Others will chime in but most here acquire their MLB from local brew supplies or online from sites like morewine.com, etc. I used VP41 this harvest.

What type of grapes/wine red or white?

Have you hit the wine with Potassium Metabisulfite(Kmeta) or campden tablets yet? If not you'll have a better chance of getting MLF to kick off.

Good luck and welcome.

Hey! Thank you for your response, the grape i most closely managed to identify was catawba. It is an old vine and every year I rue letting them go to waste. It has produced a pleasant rose colour, red, but no tannin, which matches all other descriptions of catawba. I have used campden tablets... Prior to primary fermentation, I also washed the carboy with a stirulent before adding the must.

I am planning to try use some deacidifying agent to knock the acidity down a knotch before I bottle and store the wine!
 
A few tools will immensely help know what is going on; pH meter and a hydrometer. The answers to your question will depend on if your wine is flawed or just plain acidic. Were the grapes harvested too early? As grapes mature, the acidity drops and the brix (sugar content) increases. I have found that mlf will round out a wine; changing the pH by .1 or .2.
 
Before you go adding to the whole batch, take a small sample and add your chemicals to it. Add and taste and if it does not improve the sample probably wouldn't try it on the whole batch. Might try adding a bit of sweetener to a glass, sugar or honey. If it helps make sure you stabalize before you sweeten the batch or it will probably take back off and give you a referment. Arne.
 
Also lets not forget that at 2 months from the start of fermentation most wines will have a strong tart or sour component to the taste. It may just need time, some oak while aging may also help.
 
While it may be true that your wine is just young and harsh, it's more likely that your must was acidic from the start. The way to know this is check the pH and TA. These numbers would determine the next best move. The solution most likely will turn out to be KHCO3 and then SO2/sorbate/backsweetening for balance.

Not sure you want to MLF catawba wine, at least I've never seen that done. If you have treated with SO2 it will be difficult to get MLF going, and if the wine pH is below 3.1 that will make MLF difficult as well.

Blending could be another option.

Much written about pH and acid adjustments in wine, lots of good web pages out there.
 
It's early days. Taste is not a big determinant at this stage. Did you ferment on skins? You really should take a pH reading. Cheap little pH meters can be got online. My suggestion is that you rack the wine and store in your carboy / s for at least six months. Keep the airlock on. Rack every two months and use potassium metabisulfite to keep the bugs away. Re access taste and acids etc after six months. If you want to oak, do it then. But don't over complicate what you have right now, if you think you have a problem. All the best.
 
So in regards to the pH, I have measured it throughout! Its remained above 3 and below 4. Using pH strips so its quite hard to be precise.

Thank you for your advice!

It's early days. Taste is not a big determinant at this stage. Did you ferment on skins? You really should take a pH reading. Cheap little pH meters can be got online. My suggestion is that you rack the wine and store in your carboy / s for at least six months. Keep the airlock on. Rack every two months and use potassium metabisulfite to keep the bugs away. Re access taste and acids etc after six months. If you want to oak, do it then. But don't over complicate what you have right now, if you think you have a problem. All the best.

I did indeed ferment on skins. The one issue I have with racking so often is that it exposes the wine to oxygen... I would be transferring from a 27 litre (7 gallon) glass carboy into a food grade plastic ... Would this not encourage acetic acid formation?
 
You’ve got a 7 gallon glass carboy? Never seen them before. How much wine do you actually have? Your gonna want a vessel sized so there is minimal airspace. If your topped up in the current carboy you can rack
Into the plastic vessel- clean out the gunk in the carboy and then rack back into it. Should be your main concern at this point- to let it age for the wine to come into its own. As long as you keep the vessel topped and the wine sulfited there’s no need to worry about the o2 exposure from racking. The right amount actually helps the wine age.
Without knowing exact ph don’t mess with the acid since 3.0-3.9 is too broad. 3.6 would be ideal. Every response has been good advice here.
@Venatorscribe said it well with “don’t overcomplicate things”. Re-assess after Father Time does his thing.
 
You’ve got a 7 gallon glass carboy? Never seen them before. How much wine do you actually have? Your gonna want a vessel sized so there is minimal airspace. If your topped up in the current carboy you can rack
Into the plastic vessel- clean out the gunk in the carboy and then rack back into it. Should be your main concern at this point- to let it age for the wine to come into its own. As long as you keep the vessel topped and the wine sulfited there’s no need to worry about the o2 exposure from racking. The right amount actually helps the wine age.
Without knowing exact ph don’t mess with the acid since 3.0-3.9 is too broad. 3.6 would be ideal. Every response has been good advice here.
@Venatorscribe said it well with “don’t overcomplicate things”. Re-assess after Father Time does his thing.
Hey, yeah! I have around 25 litres =D. I was thinking of bottling in the next two months and then forgetting about the wine for a good while...
 

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