Is very slow fermentation normal?

[Epimetheus]

This batch seems to be fermenting very slowly. Is this within the expected range?

It is a 3 gallon batch pitched over the previous trub. Started at 1.059 (14.5 brix on the refractometer) and after 10 days it is 1.043 (10.5 brix).

Ambient temperature is 62F to 70F, the wide range is because I turn up the heat when I work in that basement room.

 

[flars]

This batch seems to be fermenting very slowly. Is this within the expected range?

It is a 3 gallon batch pitched over the previous trub. Started at 1.059 (14.5 brix on the refractometer) and after 10 days it is 1.043 (10.5 brix).

Ambient temperature is 62F to 70F, the wide range is because I turn up the heat when I work in that basement room.

What was the temperature of the wort on day two of the fermentation? Did you use a hydrometer for the SG on day 10?

 

[Epimetheus]

I did not measure the wort temperature. The ambient temp at that time was 66F.

I used a refractometer and converted. I have compared the refractometer to a hydrometer numerous times in the past and it has been within .003 or closer.

 

[Cyclman]

Fairly big beer, my questions would be did you pitch with a calculator and aerate extensively or inject O2? I do lots of big beers, am an advocate of O2 injectors.

 

[Epimetheus]

So do big brews have a slower fermentation? No calculator because I simply pitched over the trub. I am guessing that was not enough?

I did not think it was big but OK, I'll go with that assessment. No O2 injection and I probably will not do that. Trying to keep it simple here and not involve even more equipment.

It has never gone on this long. I can wait for 3 or weeks if that's what a bigger brew normally takes.

 

[TANSTAAFB]

Pitching a 1059 brew on a cake at 66-70° should have had you cleaning krausen off the ceiling! OK. That might be a bit of hyperbole =]
It should have had you rushing to install a blow off tube like your head was on fire and your ass was catching! And it should have finished in a few days and would certainly be done in 10. Soooo, have you calibrated your equipment? Thermometers, refractometer, etc. I'd double check all my measurements and math. And what was the yeast from that you pitched onto? Was it fresh, stressed, lots of hops...I think the viability of the yeast may be a big factor. AG or extract? Mash temps?

We need more info!

I don't consider that a big beer either...1060 is pretty standard gravity range. 1100 IIPA, RIS, or Barleywine? That's big!

 

[Epimetheus]

Probably I used weak yeast. The previous trub was sitting there an extra week and I poured off half of it. Meh, everything seems ok except for stressed/not enough yeast. I'll just let it go another two weeks and measure every 3 days.

-- edit -- This was my first extract batch in over a year so mash temps are irrelevant. I've been doing AG and got a 50# sack of DME for a break. 20 minute pale ale - a record. I could get to love this extract stuff.
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The batch is 3 gallons in a 5 gallon pail, enough headspace for lotsa krausen. Blow-ups are entertaining - when they happen to someone else. There was one vid on youtube that was absolutely precious; a bleary-eyed guy staggering into the kitchen early in the morning and exclaiming "Huh ...um... there is sh--- everywhere."

Equipment is calibrated, temp measurements via an accurate thermometer on the wall which yeah is far away from a measurement in the wort.

While waiting, this weekend I'll screw up, er, I mean brew up another batch. I got lots of organic 2-row and honey malt and a pound of Belma hops. The Belma supposedly has a strawberry character. I'll try for a strawberry honey blonde without strawberries or honey, kick it up into 7.4% Maibock territory, and use LOTS of fresh yeast starter.

 

[prohl84]

This is what an optimal fermentation would look like. From 1060- 008 in 5 days.
Photo from Boulton and Quain's Brewing Yeast and Fermentation.

 

[Epimetheus]

prohl84, very cool. Under optimal conditions it should be done in 3 days. Just a little slow at >10 days. Temperature is 12C / 54F? Isn't that in range of a lager?

 

[aarong]

If you use a refractometer while it was fermenting you have to use a calculator to adjust. The one from Northern Brewer says your SG is 1.031 which is a little better. http://www.northernbrewer.com/refractometer-calculator/

 

[prohl84]

prohl84, very cool. Under optimal conditions it should be done in 3 days. Just a little slow at >10 days. Temperature is 12C / 54F? Isn't that in range of a lager?

Yes it is a lager but it shouldn't be much different than an ale time-wise as far as fermentation; I am by no means an expert but I think the clean-up time period post fermentation is the most variable since some strains produce fewer 'off' chemicals to begin with. I think the biggest factor (at optimal temps and pitch rates) would be wort fermentability/ available nutrients; an FG below 1010 means either a highly attenuative strain or fairly fermentable wort.

If your yeast is worn out I know you can add a drop or two of olive oil- it contains the sterol esters necessary for cellular growth. I have never tried it though.

 

[ChuBru]

refractometers are not accurate for measuring FG only good for OG..i would let it go for another week or so then take a hydrometer reading

 

[Epimetheus]

refractometers are not accurate for measuring FG only good for OG..i would let it go for another week or so then take a hydrometer reading

I respectfully disagree. For the FG, I have consistently been within .003 between the refractometer and hydrometer, using a calculator that includes the OG. That is close enough for me. Others may have different experiences or need that extra accuracy for competition. I am going to let it go another week and I will compare and post readings from the hydro and refractometer.

 

[ChuBru]

I respectfully disagree. For the FG, I have consistently been within .003 between the refractometer and hydrometer, using a calculator that includes the OG. That is close enough for me. Others may have different experiences or need that extra accuracy for competition. I am going to let it go another week and I will compare and post readings from the hydro and refractometer.

yes please do that im interested in knowing what measurments you come up with...but from my knowledge when there is alcohol in the test sample refractometers do not give accurate readings

 

[TANSTAAFB]

yes please do that im interested in knowing what measurments you come up with...but from my knowledge when there is alcohol in the test sample refractometers do not give accurate readings

They don't but there are calculators on line that will correct the reading within a reasonable error range. It's not perfect but the OP has confirmed the corrected reading with his hydrometer within a few points.