First batch - very slow ferment - need advice

[Tasml]

In 6 days my batch of mead has gone from an OG of 1.09 to only 1.08. On about the second day, the airlock bubbled vigorously - but stopped bubbling on about the third day. I stir daily and I can hear some bubble action, and there is a small foam layer - but no SG progress. Smells and tastes good.

Followed recipe religiously:
12# wildflower honey
4 gal bottled spring water
2 tsp LD Carlson yeast nutrient
2 tsp LD Carlson yeast energizer
1 vial White Labs WLP727 yeast

Sanitized with Star San

Boiled water
Removed water from burner and added honey
Cooled must to 82 degrees, stirred well.
Siphoned to primary bucket.
Removed yeast from refrigerator for 3 hours.
Added energizer and nutrient, pitched yeast (no starter), stirred well.
Installed airlock.
Kept at constant temperature of 70-72 degrees.
Stirred daily.

Added another 1/2 tsp of nutrient & energizer last night (no change)

What to try next?

 

[akueck]

Depending on how fresh your vial was, you either underpitched or way underpitched. One of those vials is really only good for 5 gallons up to about 1.050-60 SG.

I would do some vigorous aeration, not just stirring. You may need to add more nutrients too to help build up those yeasties (probably don't need to add more energizer). As long as it doesn't stop, a slow-ish fermentation is fine.

 

[Tasml]

Gave it a 30 sec burst of oxygen through a bubbler stone, waited a couple more days; now at 1.076. Still looks, smells and tastes good. Can hear faint bubbling in must - not enough for any airlock activity.

Can this really be OK, going so slow? Should I re-pitch, same yeast, or maybe a stronger yeast strain??

 

[Chevette Girl]

I would think that as long as it's still going and it's not making any funny smells, you're probably good.

 

[akueck]

Slow is fine. You might check the pH to see if that is low. That could contribute to a slow fermentation. If it's below about 3.3 you can bump it up slightly.

 

[Tasml]

4 weeks in and I've gone steadily from 1.090 to 1.032, still dropping. Finally got a calibrated ph reading and I'm at 2.88. Should I attempt to raise it, and with what? - or sit tight?

 

[akueck]

Oh yeah, I would bump that up to at least 3.2. Where you are now it will take a long time to ferment and probably stall early too.

Potassium (bi)carbonate is a good choice for raising the pH. Calcium carbonate is ok, but takes a longer time to dissolve and affect pH. Sodium bicarbonate (baking soda) can be used as a last resort, but use sparingly as it will leave a salty taste.

I'd try 1/4 tsp and see what happens to the pH. You can always add more if needed.

 

[ken_schramm]

2.88 - that's your problem. Slowly add a tsp of calcium carbonate (your mead will foam). If the mead does not pick up in short order (6-8 hours), add another.

A pH below 3 is stressing your yeast out. If you have a meter, shoot for 3.4 - that should give you enough headroom to make it through the fermentation and still not provide a welcoming medium for marauding micro-organisms.

Some honey has a very low pH to begin with. It's partly varietally-based, and also varies by location. Looks like you found one.

Ken

 

[wayneb]

Potassium carbonate (or potassium bicarb) will also work if you cannot get calcium carbonate. I personally prefer the potassium compounds because they dissolve more completely in water, and they react quicker than calcium. But each to his own, YMMV, etc. ;D

 

[Tasml]

Thanks everyone, over the last two days I have brought the must up to a ph of 3.38 per my meter. Total add was about a tsp of Calcium Carbonate. Not much happening yet. Plan to sit tight for awhile.