Slow fermentation

[nicklausjames]

I have a cab franc that has been fermenting on the skins for 2 weeks. The original brix was 30 but it has only gone down to 12. Cap seems fine I have an airlock on it an co2 is escaping. It's 2 lugs.

I also have a cab sauv fermenting on skins. 6 lugs. It has bee going for a week and the brix has only gone from 25 to 23.

I have them in my garage and it's been a bit chilly. I took their temp in the middle of the day and it was just 66 probably drops some at night. I guess I am going to have an extended maceration. Wondering if anyone has any potential fixes? I do have a portable heater I could put next to it and see if that helps.

Also, I have to figure out something to do malo. The outside temp is only going to get colder here in ny. I can't bring it inside.

 

[Turock]

What nutrient protocol are you using?

 

[nicklausjames]

I didn't use any. Should I add some? I have some fermaid from last year would it still be good?

 

[berrycrush]

is 66 the must temperature or the air temperature?

 

[nicklausjames]

Must. Actually I have urea and dap not ferm aid. It is from last year. Is it good to add now?

 

[Turock]

DAP is a whole lot better than nothing. Why aren't you using nutrient? THIS is why your ferment is sluggish. Dose is 1 tsp per gallon. On the cab franc, figure what an entire dose would be for the gallon amount you have. Divide that in half and pitch it now. It should now finish for you. Do not add more nutrient after that.

On the cab sauv do the same thing as far as figuring the entire dose. Divide it in half and get the first half in now. When you get down to 50% sugar reduction, add the second half.

You MUST always use nutrient in your ferments. You MUST always step-feed nutrient as I described above. Without nutrient, you'll have slow, or sluggish ferments, and you have a high risk of H2S.

 

[nicklausjames]

No reason I just didn't use it. I'll have to use it in the future.

 

[berrycrush]

I think the temperature is the issue here. The fermentation generates heat but if the ambient temperature is too low then it will go slow. I did the primary fermentation in the closet last year and it went very fast and the must temperature shot up to 80s. This year I am doing in the garage and I noticed the it started at around 67 and creeps up to 70. I can hear it is slower by the sound of fizzing. I also noticed it doesn't have strong green bean aroma of last year which could be attributed to the high temperature. In your case I would try insulate the vessel a little to keep the heat in but not too much, 70F should be ideal.

 

[Treeman]

What is the fermentation container? Have you done any punch downs of the cap?


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[grapeman]

All good questions and comments. Also what yeast are you using- some tolerate cooler temperatures than others. Definitely need to punch the cap down especially on the one that has hardly moved.

 

[nicklausjames]

2 to 3 punchdowns. Franc is in a plastic "garbage can" fermenter. Sauv is in a stainless tank. Yeast is Pasteur red.

 

[Treeman]

Agree that you could use to get the temp up into the 80s not only to finish but also to get some extraction out of your cab franc skins to balance all of that alcohol. When moving it inside to warm up, or adding some heat to the garage, I would keep the DAP on hand in case it gets stinky. Probably close enough to finishing that you don't want to add to much nutrient.

At 30 brix you have the potential for 17%+ alcohol and pasteur red may not get it dry, so you may need to add a starter culture of some EC-1118 or another yeast that will take it dry.
Get this going in a gallon jug and slowly feed it the cab franc just until it is going strong. I'd keep doubling the volume with cab franc juice every 6-12 hrs as long as its fermenting well, you can then add it to the bulk ferment when you get to a gallon.

Cab sauv should finish with pasteur red, but again think you would want to get the temp up and get some more complex nutrient than DAP to add.


Cheers!

 

[nicklausjames]

Has anyone seen one of these? http://www.brewuk.co.uk/immersion-heater.html

Are they only available in Europe? I also see they have the European plug. I have not been able to find one in the us.

 

[DoctorCAD]

An aquarium heater, nothing special. You can get one at any pet store.

 

[Turock]

The must temp is also low because the ferment is not very active--because of no nutrient.

 

[nicklausjames]

So I added the dap/urea and brought the franc into the basement where the temp is a little warmer (68). I also put a space heater next to it. This must have helped as there is a lot of activity in the airlock. I also ordered a aquarium heater online. Does anyone use these? Do u put them directly in the must?

 

[TonyR]

Hi Nick, i am no expert but when i ferment my grapes i do it in a big container with the lid just resting on the top. You need a lot of oxygen during primary fermentation. I punch down the cap and stir very vigorously 3 or 4 times a day. Right before fermentation is complete I press and put into carboys with airlocks.

 

[cintipam]

DoctorCAD, what is the preferred wattage for those aquarium heaters for use in a 10 or 20 gal Brute? They come in a wide variety of power levels, and I know nothing about aquariums at all.

I love my Brutes esp for the lids. They don't seal tight so I go ahead and snap them on. Lots of pets in the house, plus an often otherwise occupied hubby not paying attention to where he is walking.

Pam in cinti

 

[nicklausjames]

I purchased a 75 watt for 15 gallons.