View Full Version : Stuck Fermentation with White Labs Sweet Mead Yeast

01-17-2013, 12:14 PM
I did something wrong last night that stopped my fermentation, but I don't know what:


15# Tupelo Honey
Bottled Spring Water to 5 gallons
(1) tube White Labs WLP720 Sweet Mead/Wine Yeast - used same day as bought locally (3 months until expiration)
3/4 tsp Potassium Carbonate (recommended in instructions that came with Honey/mead kit)
OG 1.11
Starting temperature and temperature throughout fermentation has been maintained between 70 - 75 degrees as recommended by White Labs

Staggered Nutrient Additions

Mixed 1 tsp Fermaid K with 2 tsp DAP
Added 3/4 tsp after yeast pitch, 3/4 tsp after 1 day, 3/4 tsp after 2nd day and saving last 3/4 tsp for 30% sugar depletion

After 1 day, very frothy inside bucket and airlock bubbling well
After 2nd day still bubbling well

With each nutrient addition, I stirred vigorously. Stirring equipment sanitized with Starsan

Last night used hyrdrometer - 1.09 reading; did not add nutrients waiting for 1.08 - just stirred vigorously. Stirring caused bubbles on top. Airlock was bubbling slower than previous night, but still bubbling prior to opening the bucket.
Unlike previous nights when airlock bubbling restarted soon after re-sealing bucket, there has not been a single bubble in 12 hours. There is no internal pressure on the bucket lid and the S-airlock liquid is at "50-50." All previous days the pressure from inside the bucket quickly pushed the liquid (water w/ Starsan) all to one side quickly and started bubbling again.

What did I do last night to stop the fermentation? The stirrer and hyrdometer were sanitized in properly diluted Starsan, although I did not rinse them off with fresh water before putting in the mead. Could the Starsan have killed the yeast?

Was stirring vigorously the right thing to do? It is my understanding that I want to add oxygen.

Should I add my last 3/4 tsp of nutrient mix now?

Should I be using a different nutrient mix?

Should I buy a pH testing kit? I have never tested for pH.

Should I buy more White Labs yeast and re-pitch?

Thank you for your help!


01-17-2013, 02:17 PM
Id check the pH, you could just get some test strips for a cheap and easy way to see where things are (get the brew range ones, mine go from 2.8 to 4.4 I think). In a perfect world, your pH would be 3.6 or higher.

Stirring is good up to the 1/3 sugar break. If your pH is ok, I would add more nutrient. Its also good to note that airlock activity is not the best way to judge fermentation. Take hydrometer readings like you have been to see how things are really doing. I wouldnt re-pitch yeast yet.

Medsen Fey
01-17-2013, 02:50 PM
I'd consider adding another tsp of Fermaid K to give additional nitrogen and to act as a buffer.

Then it would be good to check pH to make sure it is above 3.2 which means you might need a bit more bicarbonate. To test pH you either need a meter or test strips with a range that gets down to 3.0 - be careful not to by an acid test kit as those are designed to measure titratable acid, which is not what you need.

Sent from my DROID RAZR using Tapatalk 2

Marc F.
01-17-2013, 06:37 PM
Are you sure your lid is on properly?

If you press the lid gently very slowly, does it move the fluid in your airlock? (If it's a bucket.)
If not, you may have a leak somewhere and it still can be fermenting.

01-17-2013, 08:48 PM
Yep, I'll second the simple solution of checking the bucket seal. Those things are not very tight, and some folks will get complete fermentation without a single bubble through the airlock.

01-18-2013, 01:17 AM
akueck and Marc,

When I read your reply at work today, I felt certain that the lid was sealed completely - last night I was sure that I had pushed the edges down hard and clicked the lid into place all the way around. When I got home tonight (still 50-50 liquid in the airlock and no bubbles), I pushed down on the lid and the level in the airlock moved with my pushes. I also pushed my hand down around the edges of the lid - and guess what: all of a sudden the lid "inflated," liquid moved to one side of the airlock and it started bubbling!

I sterilized my equipment, removed the lid and took a hydrometer reading. It was 1.08 (compared with 1.09 last night)! Whether it was the lid edge, or the gasket seal around the airlock, I had a leak somewhere. Thank you so much for your advice; I thought I had done something worse. I could not reconcile the immediate change in yeast activity myself. Do you expect that there was much risk of contamination because of the leak?

Medsen and triarchy - thank you for your replies also. I will get some pH test strips so that I can start monitoring my mead better.

Best regards,


01-18-2013, 03:45 AM
<snip>Do you expect that there was much risk of contamination because of the leak?</snip>

Almost zero. Actively fermenting must is pretty resilient to infection provided it's not just sitting completely open to the air, and even then it is still relatively safe (our ancestors have been doing it for a few thousand years). People on here have had all sorts of potential contamination scares (like a ferret swimming in some mead...) with no ill effects. Granted, the odds of an infection from a leaky bucket seal aren't completely zero, but they are pretty darn close.

Chevette Girl
01-24-2013, 10:51 PM
Glad your problem was so easily solved!

;D This is another example of why we use the specific gravity to determine the state of your fermentation, rather than airlock bubbling. If the SG is changing, you're getting fermentation... I do have one bucket whose seal is so leaky that it's never once had the airlock bubble and I even put in a solid stopper on an active fermentation once when I needed its airlock for another batch...