Should I splash-rack (sulfur)?

[FunkyMunk]

So, long story short, I brewed 5 gallons of graf, mixing 1/2 fresh apple juice (with 80 ppm sulfite added by me and left to sit for 48 hours) and 1/2 beer wort (specifically, BierMuncher's Oktoberfast Ale recipe). I used Nottingham yeast, pitched dry; I definitely noticed a rotten egg smell a couple of days after pitching, and it stuck around through the end of fermentation. After sitting untouched in primary for 16 days, I racked it to a corny keg, purged 10X and sealed with 30 psi. It is clear, and tastes alright for just coming out of primary, but is overwhelmingly sulfury.

Will this sulfur age out with the graf sealed in a keg? I did a gentle auto-siphon rack from the bucket I used for primary, but after witnessing all the sulfur I'm now worried about mercaptans forming while it sits in the keg. Alternatively, is it worth the trouble of doing an additional rack to a new keg and trying to aerate it a bit to disperse the sulfur?

EDIT: I did add 2g Fermaid O (on top of the 1.3g yeast nutrient added to the brew) when I first noticed the sulfur smell, and it didn't go away at all, so either I didn't add enough or nutrient wasn't the issue. The temp was 64-66 F throughout fermentation. Also, I'm curious whether aging in a carboy with an airlock would be more appropriate to aging under pressure in a keg.

EDIT #2: Did some more research and found another option: bubbling CO2 through the liquid-out side of the keg, through the dip tube, venting it out at the top. This seems pretty easy since it's already kegged, and if it works will have the added bonus of introducing much less oxygen (I know there's apparently a minute amount of O2 in a CO2 tank, but it would still probably be better than racking it out of the keg into open air). I'll probably try this when I get a chance today or tomorrow. Would love to hear whether this method has worked for others out there.

 

[ten80]

I have also had sulfides in several graffs where I pitched ale yeasts. I think the ale yeasts become stressed from lack of nutrients.

Avoid oxygen exposure. There was a discussion of this a few weeks back and I found a research study showing that sulfides plus oxygen can produce more stable (less volatile) sulfur compounds that are difficult to remove. Bubbling CO2 through the keg is safe. Also, I've had success boiling a 2-3" long piece of copper pipe, then dropping it into the keg for 2-3 days and racking to a fresh, CO2-purged keg. The sulfides bind to the copper and are left behind.

 

[FunkyMunk]

Yeah, I figured between the malt and the nutrients I did add, it would be ok, but i guess I'll try doubling the nutes next time.

I bubbled some CO2 through the keg, and decided to throw it in the kegerator and start carbing it up. I just tried it after a few days and it's still super sulfury. I set my regulator to 14 psi so it's only partially carbed. I will try some copper pipe in the keg. Will I be able to taste the difference if I leave the keg hooked up to the tap, just to see if it's done the job before I transfer it to a new keg? And will the carbonation be a problem when moving it? Should i do a closed transfer or open, or does it matter?

 

[ten80]

I added the piece of copper 1/2" copper pipe into the keg, then shook the keg several times daily to get good contact. I sampled the beer each day until I could't detect any sulfur (maybe 2-3 days). I then transferred to another keg using a liquid post to liquid post jumper hose in order to minimize oxygen exposure and to avoid losing carbonation. I've never had a cider get "oxidized" in the same manner as a beer might (i.e., stale cardboard flavor), but I like closed, pressurized transfers because you don't get a foamy mess and the odds of contaminating the cider are reduced..

 

[FunkyMunk]

That all makes perfect sense. Thanks! I'm actually set up to do pressurized closed transfers, and it has seemed to make a difference in the aroma since I started doing it. I just kegged a cider using closed transfer from a carboy (gravity, not pressurized) and it turned out pretty great.

 

[FunkyMunk]

Well, one day after adding the copper, the sulfur is still there but it's gone down a lot. It's still not fully carbed, and I think it could use a little aging before it tastes good, but now I realize that I don't actually know what graf is supposed to taste like...

 

[ten80]

Well, one day after adding the copper, the sulfur is still there but it's gone down a lot. It's still not fully carbed, and I think it could use a little aging before it tastes good, but now I realize that I don't actually know what graf is supposed to taste like...

Well, it's not supposed to taste like rhino farts!

I'd say a graff has the crispness of cider and light apple notes with a rounded mouthfeel and more substantial body than a cider due to the malt. The acidity will be less harsh on the palate than a cider made from the same juice.

 

[FunkyMunk]

Haha, noted. I'm a couple pints in and I'd say the taste matches what you describe. My wife is very sensitive to sulfur notes in booze and wants nothing to do with it. So, I'd say it's not quite there yet. I admit I only really shook the keg twice since I added the copper, the second time being just now. I will probably rack it within the next couple of days regardless to ward off potential metallic off-flavors from the copper being in an acidic medium for so long. It has at least reached the drinkable (by me) stage, and hopefully racking + time will take care of the rest.

 

[FunkyMunk]

As I was researching this, I came across this thread, which discusses the issue of sulfides, mercaptans, etc. in cider at length... what's interesting to me is that it seems that sulfides may not necessarily "go away" completely, but rather react with other compounds to produce mercaptans and disulfides, which have higher thresholds of detection, thus are not as noticeable but still "there", so to speak.