Cold Soak?

[jsbeckton]

Curious if many people have tried this? I’m looking to try to increase extraction of color and flavor from a Syrah and will be working with a batch small enough where I can easily control temp to keep it where I want it for however long I want to.

Questions that I’ve been mulling over:
1) How long? Thinking 3-5 days.
2) What temp? Thinking 50-55F.
3) Do I still use enzymes? Thinking I will during last day as it warms up.
4) Do I need to take any extra precaution for O2 exposure? Thinking I will just crush into buckets and try to keep them as full as I can and leave lid on.
5) Should I stir and how often? Thinking 1-2x a day.

Any thoughts? Thanks in advance.

 

[mainshipfred]

This probably won't be much help since it has only been aging for a month or so. I did a cold soak on a blueberry for 10 days after the adjustments and enzymes were made. Had it in a chest freezer at somewhere around 40*. It is very dark but I'm told blueberry is dark anyway. I did add sulfites at 50 ppm.

 

[jsbeckton]

Hmm, not a lot of responses makes me a bit worried to try this. Guess I’ll see how dangerous I feel next week!

 

[Ajmassa]

Hmm, not a lot of responses makes me a bit worried to try this. Guess I’ll see how dangerous I feel next week!

Im sure you’ll get some insight eventually. I’m interested to hear too. I think* all your instincts are on point and I agree with mostly all.

1. Time-length—3 days? 10 days better? No clue. I think your 5 day approach works
2. I don’t think it’s dangerous tho as long as it’s kept super cold. My guess is as cold as possible w/o freezing. So definitely colder than 50-55°. My gut says 30’s
3. Enzymes. My guess is NO for the soak just like you said so not OD’ing on tannin
4. Full buckets w/ lids sounds ideal
5. Stir 1-2x/day is exactly what I’d think too

probably would give it a small dose of kmeta to be safe too. Targeting 30ppm or something. plus any acid addition if needed

 

[stickman]

I tend to generally agree with the above comments, but the end result depends greatly on the chemistry of the grapes. All you can do is try, and gain experience with what works for the grapes you have on hand. There are so many factors involved that it's almost impossible to understand what's happening at a technical level. For a cold soak, I would check the grapes to be sure they are fully ripe, preferably no green seeds.

I usually add 35ppm SO2 to keep some of the bacteria in check, if adding enzymes I'll do it the following day. If you are going to play around with pH, adjust to your target as desired. From what I see, temperatures below 50F are adequate to keep the non-Saccharomyces yeasts working at a slow but reasonable pace. SO2 will not have an effect on Kloeckera which tolerates 70+ ppm SO2, and is naturally cold-tolerant. Normally there are no problems, but Kloeckera can produce some off aromas like ethyl acetate, amyl acetate, as well as volatile acidity, so keep checking with your nose to ensure this doesn't get out of hand. Inoculate with desired yeast if any off odors are detected.

 

[jburtner]

Last fall it was getting cold out and I put the brute full of grapes in the dungeon room which is exposed to the outside with no HVAC. I think it was in the mid 40’s to low 50’s. Those were carignan grapes and I let them start ferment slowly with the wild yeast. It went pretty slow for 10-14 days or so before I pitched a yeast starter so it got a good cold soak with enzymes, tannins, and nutrients and started out with the wild yeast. I did not SO2. AF may have been a full month or so. Not very scientific or controlled but it was definitely cooler than what I normally do and an extended ferment. I’ll do it again next fall and it’s turned out quite well so far. I did a second cab sav juice bucket ferment on the skins the same way right after although with the yeast left in the skins and that was slow and lovely as well.

Cheers!
-johann

 

[winemaker81]

I'm interested, as well. For me the hard part is maintaining temperature. I'm in the middle Atlantic (USA) so keeping the grapes cold will be a trick. I'm looking to purchase ~600 lbs of grapes next fall, so putting it in the fridge won't work.

I'm wondering if bags of ice around the Brute would work, or dry ice.

 

[winemaker81]

I was searching for cold soak threads when an idea came to me -- freeze some of the grapes in 2 or 3 lb blocks. Place a block in the brute and stir (I'd stir at least once a day, anyway). When the current block melts/defrosts, add another one.

I don't have evidence (yet) to determine time frames, but I'm thinking that if I want a 10 day soak, I'd add the last block on Day 7, as once the last block is melted/defrosted, it will take a couple of days for the must to warm up.

 

[zadvocate]

I have done a few days cold soak, maybe 3 days. If you look online and in podcasts you will see alot of winemakers do it but the time frames vary. I think the most important thing is to keep it cold. Get Ice bombs, enough to be able to add them 2 times a day. So depending on the time of year, you just add one or two ice bombs and monitor the tempature. Lately I just add the enzymes instead, they seem to work just as well.