Campden Tablets

[Ryue]

Hey ya'll,
I know this question has probably been asked a thousand times, but I figured I'd duck my head and ask anways..
So I have a cyser that started at 1.116 and is now at 1.010 (13.6%abv), it is still fermenting, though extremely slowly. I like it as is and would rather avoid having to backsweeten if I can..
My question is, will adding campden tablets stop further fermentation? If not, what do I need to do? And will halting the process at this point throw off flavors?
Thanks in advance!

 

[bernardsmith]

Campden needs to be added WITH sorbates (K-sorbate) BUT if you have a healthy and viable colony of yeast that is actively fermenting the remaining sugars then stopping the fermentation in mid-flight is a bit like trying to catch a bullet between your teeth . Sure, magicians and illusionists seem to be able to do this on TV or on stage... but they are illusionists.
So what's the trick here? At the risk of being thrown out of the magic circle for giving away the secret you might need to rapidly near freeze the cyser to allow the yeast to drop out of solution; rack the cyser off the yeast. Repeat. Perhaps repeat one more time and then add the K-meta (Campden) and K-sorbate cocktail. (you are then stabilizing the cyser with very few yeast cells) But see - this process can take several days, perhaps a week.. so catching this bullet between your teeth might require the bullet to be flying at perhaps 1 mile per hour...

 

[Yooper]

No campden will not stop fermentation- it's used as an antioxidant.

If fermentation is slowing, it's likely nearly done anyway. Trying to stop it may cause some stressed yeast, which produces off flavors.

Which yeast strain did you use? You may be at or near the alcohol tolerance of the yeast strain and it will stop on its own if so.

 

[Ryue]

I used Red Star Premier Blanc yeast, which has an advertised abv of 15%, but in the past it had gone to 19.5% on me..
I suppose I will just ride it out and if needed I will backsweeten.
If fermentation done, will just Campden be enough to keep it from fermenting more if I sweeten, or do I still need to add k sorbate?

 

[dmtaylor]

Rack, chill, and add sorbate. Done. You don't need Campden.

 

[bernardsmith]

Campden (K-Meta) is great for killing off the few dozen cells of wild yeast that may be lurking on the fruit or before you pitch the 100 billion sized colony of lab cultured yeast cells in your pack. You need to use K-sorbate and K-meta to prevent re-fermentation.
When a lab states that the strain of yeast will ferment to X% that is not a statement about the very maximum tolerance for alcohol the yeast has. That is a statement about the kind of use you can freely expect the yeast to provide. It's like the breaking strain of a piece of rope or the MTBF (mean time between failure) of an electronic component. It's the typical and the expected and perhaps even the guaranteed levels. Can they exceed this? Of course. But if you REQUIRE that they do and they fail the problem is entirely yours. And that is very different from the lab stating that your yeast CANNOT tolerate any alcohol above 15%. It's spec'ed for 15%. So don't use it for higher alcohol wines and meads.

Oh, and by the way, yeast don't die when you exceed their tolerance. They simply stop fermenting. Dilute the mead or the wine with water and they will start up again. And some cells will still continue to ferment at astronomically high levels of alcohol and those cells might produce daughter cells and their daughters might have daughters and you might find that your high alcohol mead has started to referment long after you assumed the yeast was "dead"...