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View Full Version : Cold soak bleached my fruit?



AToE
02-25-2011, 06:47 PM
I'm pretty sure there was a discussion about this recently, but I cannot find it. Last night I put a bunch of mashed berries (about a gallon of saskatoons) into a pot with 1tsp sulphite and 1tsp pectic enzyme to cold soak in my fridge overnight. Immediately after adding the chemicals I noticed it looked whiter and cloudy, and today I open it up and it's pretty much lost all it's colour, it's pretty pink.

What the heck happened here? I half-remember the other discussion someone saying the colour would come back, but that seems impossible when I look at this bleached pot of fruit (and I'm not known for my memory)...

If I just killed all the colour in $25 worth of fruit I'm going to be sad! I'm damned well going to ferment it anyways, maybe to use for blending later, but still, this is terrible!

wayneb
02-25-2011, 07:13 PM
I can't find it either, so I'll answer your question! ;)

SO2 can bind with anthocyanins in your must, turning them into a mostly colorless compound. The reaction is reversable, and as SO2 levels in the must drop (when the sulphites bind with other compounds or when free SO2 escapes to the air) much of the color will come back.

AToE
02-25-2011, 07:31 PM
Excellent, it's good to hear that! I may still toss in some wild blueberries for more colour, in a small enough amount they shouldn't alter the taste much.

Fisher kel Tath
02-25-2011, 10:39 PM
Yea, happened with my blood orange mead too, I juiced a couple extra oranges for the transfer and stabilising, and it instantly turned the black juice white...

AToE
02-26-2011, 02:53 PM
Was 1 tsp sulphite way too much? I find myself thinking a 1/4 tsp would have been more appropriate. Obviously by weight would be better, but still, ballpark guesses?

I ask because I pitched 8 grams of RC212 into this last night, more than 24 hours after sulphiting it, and before pitching I stepped the yeast up with small must additions and it was very active. Today, it's totally silent, the fruit isn't even floating, it's sunken - so really, absolutely no CO2 being produced right now.

I'm not super worried about it, I can just pitch another pack of RC212 if necessary, but figured I should ask about this since this long of a lag with 8g of yeast in about 1.5-1.75 gallons of must is really long in my experience. Similiar circumstances (room temp) have always started up in a few hours for me. (Like I said though, I know it just goes slow sometimes, not worried).

wayneb
03-01-2011, 12:29 AM
Neglecting any binding of the sulphite, one eighth teaspoon metabisulphite per gallon will contribute roughly the same amount of free SO2 as one campden tablet - around 50 ppm, give or take. So using 1/4 tsp per gallon is around 100 ppm, and using on the order of 0.75 tsp per gallon (per your recipe, 1 tsp per 1.5 gallons) is dosing at around 300 ppm. Yeah - you hit it pretty hard, even allowing for some binding with those red fruit tannins/anthocyannins.

If nothing happens in the next 72 hours, then I'd pitch more yeast - and to make sure something gets going, it might be a good idea to acclimate the rehydrated yeast by adding a little of the sulphited must along with some plain water/honey in order to expose your yeast to a higher than average sulphite level gradually, before you pitch into the main batch.

AToE
03-01-2011, 01:03 PM
Ah good, at least I wasn't out to lunch pitching more yeast! As you can see in the brewlog for this one though, I did manage to mess up all other kinds of things!

So in the future I will use 1/8th to 1/4 tsp per gallon only!

Medsen Fey
03-01-2011, 06:12 PM
Was 1 tsp sulphite way too much?

A tad. :rolleyes:
LOL!

That's about 6 grams of KMeta, and in a 6-7 liter batch will give you 500-600 ppm total SO2. The good news is that some of it will be bound (unfortunately to your anthocyanins), and some of it will blow off during fermentation (or be metabolized) so there's a good chance it won't taste funny at all. The bad news is that it did bind up those free anthocyanins and as they are slowly released back into the the solution, many of them will bind or precipitate out and you will probably never have the color come back (at least not in a strong way).

AToE
03-01-2011, 06:15 PM
Well, live and learn. Of course, it HAD to be with $25 of fruit (not a lot, but for a 1 gallon batch it is), but oh well! I didn't even think of it effecting the taste/aroma, that would really suck.

It actually did darken up remarkably after about 2.5 or 3 days, it's pretty decently dark now, not as dark as it could have probably been though.

wayneb
03-01-2011, 08:12 PM
A tad. :rolleyes:
LOL!

That's about 6 grams of KMeta, and in a 6-7 liter batch will give you 500-600 ppm total SO2.

OOPS! I did it again - trusted my memory instead of my notes.... I was thinking 1/8 tsp per gallon = approx 50 ppm SO2, when in fact it is 1/16 tsp per gallon is the 50 ppm target. Medsen is correct, you really did dose this at closer to 600 ppm. :eek:

wildoates
03-01-2011, 08:15 PM
That's why we pay for all that expensive redundancy on this here site, Wayne. :p

AToE
03-01-2011, 08:25 PM
Ok then, so in the future no more than 1/4tsp per gallon is what I want right? If I even use any.

Medsen Fey
03-01-2011, 08:37 PM
... you really did dose this at closer to 600 ppm. :eek:

Says a lot about how tolerant wine yeast are of SO2 don't it?

wayneb
03-01-2011, 11:12 PM
Says a lot about how tolerant wine yeast are of SO2 don't it?

Well, maybe -- but he hasn't told us that it actually started up yet. ;)

wayneb
03-01-2011, 11:13 PM
Ok then, so in the future no more than 1/4tsp per gallon is what I want right? If I even use any.

Better to work in terms of ppm free SO2, which depends on pH, other compounds that can bind the sulphite, etc., but as a general rule of thumb, keeping an upper limit of 1/4 tsp per gallon is pretty reasonable.

Chevette Girl
03-01-2011, 11:51 PM
Unless you've got a specific problem with your fruit (I usually sulphite my pear batches now because they have a tendency to get fuzzy before the pectic enzyme has had a chance to do its thing) or are expecting your fermentation to take a while to start up, most nasties get choked out by a nice active fermentation, so I never bother otherwise.

I also prefer campden tablets, they come pre-measured, 1 tab per gallon, and anything that comes pre-idiot-proofed is the natural choice for me!

AToE
03-02-2011, 12:34 PM
Well, maybe -- but he hasn't told us that it actually started up yet. ;)

It started, but I added another packet of yeast about 24 hours or so after the first one, so it could have been just that packet working. This is the one in my saskatoon mel thread.