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View Full Version : A few questions on stopping fermentation



Justin
03-06-2007, 06:47 PM
I've read the search results for this but can't find what I'm specifically looking for. Chilling the mead is out of the question since I don't exactly have room for a 5 gallon carboy in the fridge. I have a bottle of campden tablets and I gather they can be used for this purpose but will they effect the flavor? I want my mead to taste it's best but I like a minimal ammount of residual sweetness. I've heard backsweetening can leave it tasting a bit strange like raw honey. My questions are,

1. Will campden tablets make my mead taste like shite and if not how much should I use.

2. What is the common method of backsweetening? (i.e. Dilute with water before stiring in, how to stir in without oxygenating, how do I keep fermentation from starting back up, etc.)

Thanks in advance for any input.

akueck
03-06-2007, 10:04 PM
I've only halted fermentation early once, so I'll give you what advice I can.

Where is your mead in it's fermentation cycle? Stopping an active fermentation is a lot different than simply preventing a resurgence when you add sugar. Active yeast are harder to knock out, so you'll need to either convince them to sleep (i.e. make it cold) or brute force them into submission (high sulfite levels). Dormant yeast are easier to handle. The yeast will naturally go dormant at the end of fermentation, so if you can it is best to wait until then before trying to add chemicals.

So let us know where you are on the timeline:
1) active yeast, active fermentation, please stop it now!!, or
2) dormant yeast, completed fermenation, just want it sweeter.

As always, complete recipe and all the gory details will get you the best answers.

Justin
03-07-2007, 12:59 AM
My question isn't really for a specific batch but I've been tending to usually stick with 5 gallon batches with 18 lbs honey and EC118 or K1-1116. This gives me about a 17% potential and Ive found I like it best with about 2% remaining sugar. So I'm asking about active fermentation and how to stop it when I get to the gravity I want.

akueck
03-07-2007, 01:40 AM
Stopping an active fermentation takes a big hammer (but only when it's intentional, killing the ferment accidentally is so much easier!). Stopping an active ferment without chilling is even harder. So, unless you really begrudge the last 2% alcohol, I'd say let them finish wherever they decide to land (which could be totally dry) and let the yeast settle out. Once it's done and the yeast is (mostly) out of suspension, add your sulfite/sorbate cocktail (if you can find a way to chill it, that is good too. try wrapping some small bags of ice around the carboy for a couple days). Wait a week or two to let the yeast die and drop out completely.

Draw some samples to decide how much honey to add for your desired sweetness level. Then rack onto some honey/water to sweeten. Racking will help mix in the new honey without stirring it up too much, but let it sit for at least a month to make sure it's evenly distributed and that nothing unexpected is going to happen (like more fermentation). If it refuses to mix, you might need to gently stir occasionally.

The sulfite/sorbate levels I've seen mostly center at 1/8 tsp K-Metabisulfite or 1 campden tablet per gallon and 1/4 tsp K-Sorbate per gallon. The one time I killed an active ferment (following some instructions) I used a lot more: 1/4 tsp KMeta and 1.25 tsp KSorbate. And I chilled it. The yeast was very dead, but that's a lot of chemicals. Best to let it finish on its own and stun some sleeping yeast instead.

If you don't want to get that last bit of alcohol, hold back some honey initially (next time). Let it go dry, then do as above to knock the yeast out and sweeten.

If you're patient, you can get rid of the yeast without chemicals simply by waiting. Rack after fermentation is complete, rack again after it clears. Chilling before each racking will help get the most yeast out of suspension. I've never used them but I'm guessing fining agents would help some too. A few rackings later, nearly all the yeast should be gone and/or dead. This could take a long time (probably minimum one year), so you'd have to be willing to wait. But it could be worth it.

As I said, I only have the one experience with sulfite/sorbate treatment. Hopefully others will correct me if I'm wrong.

Also, if you like the residual sweetness you should try a yeast with a lower alcohol tolerance. Try 71B or D47, which knock out at around 14%. Then the fermentation can complete on its own and leave sugar behind--no need to mess with it.

Rhianni
03-07-2007, 10:21 AM
AKueck is pretty much spot on. 1/4th tsp sulfite is way too much and I did that once by grabbing the wrong sized spoon. I am still holding out hope it will be drinkable but its been a year in the bottle.
1/8th tsp is plenty enough and I am actually going to start under messuring it. 1/4th tsp sorbate is about right. Both work together.
These really only work when the yeast is slowing down. Think of it as a hill. If the yeast is out of control its going to drive right over the chemicals and keep going. If its slowing down it will be enough to stop the fermentation.

Ideally on your next batch add in a couple extra lbs of honey so that the yeast will stop on its own naturally and you will have your prefered sweetness. Or switch to a yeast that stops at like 15% and use the same amount of honey.

Noob
09-08-2014, 09:46 AM
as far as i studied about nature of yeast, no matter now much you cold them they still live, even if you put them in dry ice they still survive about 6 months! indeed persistence small beings!
Sorbate and no use on active fermentation. method sorbate do is similar to penicillin, it stop any bacterial or yeast from dividing and making more Yeast babies :P

so in active fermentation as long living yeast consume sugar and not dead sorbate standby whenever they want make yeast babies put stop to it ;)

so why cold & sorbate cold make them slower on consume and gather around each other and get lees due getting heavier in bottom of your jug or carboy.

however about chilling method make sure if temperature goes below 0 Celsius, don't disturb lees, on racking,
cause while yeast goes dormant in low temperature ice crystal scratch and change yeast nature "yeast mutation", usually make off flavor in your final product.

in the end i think best method is as mentors said let it stop fermenting.

if you dont want high abv
try check out yeast with lower alcohol tolerance, so they die naturally. or keep chill and rack till no more lees in your carboy. and add sorbate in small amount, to prevent persistent ones, don't keep grows in your mead/wine/melomel.

i guess that's all i know, i appreciate if any more information or im wrong in any part let me know too as well

Cheers :cheers:

GntlKnigt1
09-08-2014, 11:23 AM
Or lower the pH below 3.0...2.8 or less is good. Hopefully, creating a "stuck fermentation" is what you want at a certain SG

Noob
09-08-2014, 12:27 PM
awuch PH 2.X is way to tarty lol i don't think personally i can handle that much acid

GntlKnigt1
09-08-2014, 12:31 PM
Coca cola is pH 2.5. If you can handle that.....

Noob
09-08-2014, 12:44 PM
lol no wonder i dont like Coca cola too hahaha

it always upset my stomach and yeah co2+water make carbonic acid thats why they put tons of sugar to make it sweet totally bad for health all the way

Medsen Fey
09-08-2014, 01:23 PM
Just remember that sorbate alone is not reliable for preventing yeast from restarting. You need to combine it with sulfite (KMeta) for it to be effective. Also, if you use sorbate alone, lactic acid bacteria can metabolize it creating a geranium odor that you can't remove.

Noob
09-08-2014, 02:03 PM
wow good quote, i dont want make my meads smell stinky socks hehe

what combination work best Medsen i mean between Sorbate & Potassium metabisulfite(KMeta)


Just remember that sorbate alone is not reliable for preventing yeast from restarting. You need to combine it with sulfite (KMeta) for it to be effective. Also, if you use sorbate alone, lactic acid bacteria can metabolize it creating a geranium odor that you can't remove.

Medsen Fey
09-08-2014, 02:24 PM
1 g/gallon of potassium sorbate and 1.5 Campden tablets per gallon (for KMeta) will usually work. Just make sure to watch it for a few weeks before bottling to be sure.

Noob
09-08-2014, 02:32 PM
good thanks, no campden tablet here like rest of winery equipments here, so i have to buy material and mix them up myself.

thank you Medsen

Cheers :cheers:

Medsen Fey
09-08-2014, 05:10 PM
Potassium metabisulfite 440 mg equals 1 Campden tablet.

Noob
09-09-2014, 01:26 AM
thanks now i can make my own campden tablet :D

kudapucat
09-09-2014, 06:55 AM
You really need to stall it before sulphating and sorbating.
If you have room, grab a second hand fridge off Craig's list. They're often free (I have 2)
If you can't chill, then drop the ph (you can raise it again)
Otherwise you could pasteurise, but it's way too much hassle IMHO (never tried)
Good luck.

Medsen Fey
09-09-2014, 07:45 AM
If you can't chill, then drop the ph (you can raise it again)...

This may be a very difficult thing to do, and will have a HUGE impact on flavor because even if you have shifted the pH back the titratable acidity will have been increased.

kudapucat
09-09-2014, 11:02 AM
This is true, but without a fridge... It gets hard...
I was commenting on the statement that he didn't like drinks < 3 pH.

Medsen Fey
09-09-2014, 11:15 AM
That's why it is better to start with a gravity that produces the desired ABV, let it ferment dry, then when the yeast stop on their own, go ahead and stabilize. Then you can backsweeten to the optimal balance point.

kudapucat
09-09-2014, 11:26 AM
Or to start with a gravity that exceeds the yeasts tolerance, though there's less control this way. - but it's the method I prefer.

Noob
09-09-2014, 02:04 PM
yeah unless have strong yeast and make rocket fuel, so check yeast tolerance before use this method

edblanford
09-09-2014, 02:14 PM
I started a batch with 71B (12-14%) that had a potential of 16% and had it stop short (about 14%, 1.008 sg) which is where I wanted it. From my experience (limited at best), if all fermentables are added up front (not step fed), the yeast will stop in the neighborhood of their advertised abv. Just sayin.

Midnight Sun
09-09-2014, 05:11 PM
There are many factors that can influence when yeast stop: nutrients, fermentation temp, quantity of yeast pitched, aeration, acidity, etc. If you treat your yeast well, there is a good chance they will ferment past their ABV. Treat them poorly and they may stop before the listed ABV. Since healthy yeasts = cleaner fermentation, I prefer to treat mine well. For this reason fermenting dry and backsweetening works best for me.

Noob
09-10-2014, 02:22 PM
well, the question i have isbit different than others,

lets say if you want make very low alcoholic drink, usually wine yeast tolerance 12~16% abv

if you put like 7% sugar in start, what will happen to yeast? will they die from hunger or like ninjas keep staying there till more sugar come eventually and start over again?

kudapucat
09-10-2014, 04:52 PM
Ninjas. But sleeping ninjas, who can wake up without warning.
Best bet is, kill them in their sleep (KMeta) and cut their gonads off (sorbate)
How to tell when they're sleeping? They all lie down together (yeast cake in the bottom of carboy)

Noob
09-10-2014, 06:53 PM
cool i gonna try this off to make lower abv melomel see how it goes.

i update how it goes.

cheers :cheers:

Ninjas. But sleeping ninjas, who can wake up without warning.
Best bet is, kill them in their sleep (KMeta) and cut their gonads off (sorbate)
How to tell when they're sleeping? They all lie down together (yeast cake in the bottom of carboy)

Noob
12-19-2014, 04:56 PM
:confused: ok as you mentioned i made my own campden/kmeta powder 1g/440mg Potassium metabisulfite,

my Pomegranate melomel is done dry about 9.5% abv

i had bit issue with clearing out too,

anyway i added to portion of my melomel to test it before add it to my gallon and tnx god i did that :o

look what happened when i add it to it
some reaction happened its look like starch in lukewarm water thats best i can describe it!
here is photo perhaps someone explain whats going on im super confused to the core ???
right one is finished melomel left after added the compound!

http://mycard.ir/img/weird.jpg

ostensibly
12-19-2014, 05:13 PM
to be clear, you mixed 440mg of potassium metabisulfate with 1 gram of potassium sorbate for the one gallon batch, then added some to the sample? how much did you add? much more than a pinch would probably be too much for what appears to be a small glass.

Noob
12-21-2014, 03:15 PM
i disolved it to lukewarm water then try to test it in with portion of my Pom melomel, result is what u c, funny part was it it change color or pom instantly!
as soon it hit the surface of that glass on right it turn that color!.

i wonder now how am i suppose to back sweeten my melomel ???

EJM3
12-22-2014, 02:15 AM
That is due to using a large amount of the K-Meta with a small amount of the melomel. I made a rhubarb melomel and when I added the K-Meta it bleached my sample, but I added it to my main batch and it did NOT bleach the entire batch. I even added it at twice the usual dose because of contamination and it still did not bleach my batch.

Noob
12-22-2014, 05:34 AM
thanks EJ i gonna try it and pray it don't ruin it i like back sweet it for new year,:-\
i don't like lose that beautiful red color :'( hmm i guess we will findout soon enough.

tnx fr help

EJM3
12-22-2014, 05:31 PM
Double posted for some bizarre reason when I came back to the page. :p

Noob
12-23-2014, 06:13 PM
:(

ok here is my 1 gallon batch, as u noticed i lost part of my batch due first racking

http://mycard.ir/img/together_s.jpg
ok on left pic is that sample i add kmeta powder, on right 1 my pom melomel, color changes beyond obvious.
i start added it to my batch, on right side you can see it lost that red color and turn to dark pink cloudy thingy :crybaby2:

is it lost cause or i should let it be any hope my melomel batch :(
w.o kemta all my stuff gonna stay dry and i hate dries :(