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Slow Fermentation

Hi folks,

Brewed an all-grain winter warmer on 10/12. OG = 1.065. Used a two-step yeast starter via YeastCalc (1.5L; 1.5L); intermittent shaking. As of last night (18 days), my gravity was only down to 1.030. Beer was really cloudy (suggests yeast still in suspension); the smell and taste were great. Fermentation temps have been consistently between 65F-68F. I’m planning on taking another gravity reading on Sunday. FYI, I brewed this exact same beer last year and the gravity was down to 1.013 after only 14 days of fermentation.

So, what do I do if there is no change in the gravity reading on Sunday? Should I re-aerate the wort in the primary to re-suspend the yeast that has settled at the bottom of the primary? Or, should I pitch new yeast?

Thanks,
Ryan

That sounds very shady that after almost a month your yeast is still in suspension. What yeast are you using?

Edit: I see you edited the timeframe. 18 days still seems a bit high.

Yeah, I bought the supplies on 10/6, brewed 10/12–got my dates mixed up. I’m using Wyeast 1728 (Scottish Ale). I think it’s strange it’s still in suspension too.

Since it’s been several weeks, give the fermenting beer a gentle swirl without causing sloshing, move to 70-75F, take gravity reading 5 days latter to see if it’s dropped some more. Another thought is your sample is mis-measured or your hydrometer is not accurate.

The gravity you mentioned is the odd fact. Did you mash with a lot of unfermentables?

DON’T add oxygen after fermentation has started. You might get away with it a couple hours after fermentation started. Doubtful you will get away with it 1/2 way through.

Thanks for the replies!

My hydrometer is 1.001 in H2O; I don’t understand the mis-measured part. Pulled the sample just like I’ve pulled every other beer I’ve brewed. I figured the gravity would be high once I saw how cloudy the sample was.

I didn’t add anything other than the grain bill.

Thoughts on pitching another smack pack? I’m planning on taking another reading Sunday to see if there is any movement before I take any additional steps…

What is the grain bill?

Adding oxygen will be detrimental to the beer. Even if you add new yeast.

11.50 lbs Maris Otter
1.00 lbs Medium Crystal
0.25 lbs Chocolate Malt

Sorry, should have included “mash temp” also. How accurate is your thermometer?

Doughed-in at 175F, but had to add 0.25 gallon cold water and stir for 10 minutes to get our mash temp down to 152F. Haven’t explicitly tested the accuracy of our thermometer, but it matches our HVAC temp so I’m guessing it’s okay.

If the gravity doesn’t change tomorrow, I think it’s safe to assume that it’s not yeast that’s suspended. So, what about cold crashing to get the particulates to fall out? I think the gravity would necessarily have to drop after that.

Doughed-in at 175F, but had to add 0.25 gallon cold water and stir for 10 minutes to get our mash temp down to 152F. Haven’t explicitly tested the accuracy of our thermometer, but it matches our HVAC temp so I’m guessing it’s okay.

If the gravity doesn’t change tomorrow, I think it’s safe to assume that it’s not yeast that’s suspended. So, what about cold crashing to get the particulates to fall out? I think the gravity would necessarily have to drop after that.[/quote]

Is that your typical mashing process? With my system mashing in at 175 would put me at 162-163. Im not sure how fast things happen but your high fg may be a side effect of being at such a high temp for ten minutes. I’d test your thermometer too, before I got a theromopen I was using cheap digital that was off significantly

We’ve been tinkering with our dough-in temps because we’ve missed low (~148F-150F) starting at 165F-168F; obviously grain bill has a lot to do with starting temp.

We use an analog thermometer, which matches our HVAC, oven thermometer, and the digital thermometer that serves as our pencil holder.

I’ve attached a picture of the sample I pulled this morning. Very cloudy, but smells and tastes great. Gravity = 1.030, so no movement since Tuesday. [attachment=0]glass.jpg[/attachment]

Considering all of your comments, it might be a safe assumption that the cloudiness is due to the high initial mash temp. Either way, the high gravity has to be due to the remaining particulates that we extracted from the malts.

So, do you think cold crashing the primary for a few days would work to drop these particulates out? I’ve put the glass into the fridge as a test run…

In regards to dough in temp drops, look at the temperature of the grain also. If you grain is stored colder during the winter, bring it to a warmer part of the house the day before brewing.

Sounds to me like the yeast are out of oxygen. If he were to pump some oxygen into the beer would it be a guaranteed disaster?

'[quote=“jtb”]Sounds to me like the yeast are out of oxygen. If he were to pump some oxygen into the beer would it be a guaranteed disaster?[/quote]

It’s way too late to add oxygen, it would just make things worse IMHO.

Good point!

From what I’ve read, doughing-in at 175F and not getting to 152F for 10 minutes extracted unfermentables out of our malt resulting in a high FG, which produced a beer with more body. No length of cold crashing will completely clear those unfermentables, but we’ll add some gelatin to (hopefully) clarify and then bottle as planned.

On a side note, is it possible to accurately calculate ABV given that the unfermentables are keeping the FG high?

I did some digging and understand why you wouldn’t want to oxygenate.

What will you do you think you’ll do differently to prevent this from recurring?

Doughed-in at 175F, but had to add 0.25 gallon cold water and stir for 10 minutes to get our mash temp down to 152F. Haven’t explicitly tested the accuracy of our thermometer, but it matches our HVAC temp so I’m guessing it’s okay.

If the gravity doesn’t change tomorrow, I think it’s safe to assume that it’s not yeast that’s suspended. So, what about cold crashing to get the particulates to fall out? I think the gravity would necessarily have to drop after that.[/quote]

If your using a cooler to mash in one thing that helped me hit my temps was pre heating the mash tun. For example if I want to dough in at 165 I add water 175-180 degree water and let the temp come down to 165 before adding the grain. The cooler will absorb a good bit of heat quickly especially if it was stored somewhere cold.

+1 We’ve done this the past few brew days. Generally we heat the water to 185F, cover the mash tun, let it sit for 10 minutes, and then open it up and stir allowing the temp to drop to our dough-in temps. So much tinkering, but we’ll eventually get it right :cheers:

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