Fermentation has slowed, and I'm getting impatient

[bill_face]

Hello all,

I've had a porter fermenting with LalBrew® Nottingham Beer Yeast for 2 weeks.

It started off with a OG of 1053, aiming for a FG of 1013 fermenting at 19C. It took off fairly quickly (krausen after 12 hours) and had what seemed like a vigorous early fermentation. Then it slowed down after a few days and I was thinking it was nearly done, but didn't take any SG readings as I try not to interfere where possible.

over a week later it was still slowly fermenting so I opened it up to investigate. SG had reached 1022. So I gave it a bit of a stir to try and get some more oxygen into the wort. It tasted a bit buttery which i imagine is diacetyl, but I'm not in the habit of tasting at this stage, so don't know how normal that is. Its also probably only my 6th or 7th brew, so I'm fairly inexperienced, but none thus far have proceeded in this manner.

There was a dip in temperature to around 15c for a day or so when I went away after xmas, but it had slowed before then. Its now back at 19C

It would seem to me that my options are to:
- leave it chugging away slowly
- warm it up a bit
- somehow aerate it
- put in some more yeast.

Just wondering if anyone has any advice

Cheers

Phil

 

[Clint]

I'd warm it up to 21c.

 

[The Baron]

I'm with Clint on this you have already roused the yeast with a stir a higher temp may help to get it going again

 

[bill_face]

So I raised it up to 21° on Friday. 72 hours later I was still not getting much air lock activity so I took a reading and it had reduced by probably less than 2 SG points. So I added the rest of the pack of yeast (it was a 11litre batch so i usually just add half a pack), which I had primed with a bit of sugary water to make sure it was working.
Have left it another 24 hours with no increase above sluggish airlock activity. (probably about one small bubble every 5 minutes)

I'm thinking I'm going to open it up, take an SG reading and if it's still well above the FG I'm going to add some yeast nutrient

I'm just unsure what effect on the taste the yeast nutrient might have at this stage

Any further input would be greatly appreciated

 

[Pennine]

Once it gets down to the 1.020 range and stops usually means it done, stalled ferments don't really happen in my eexperience and there isn't much you can do to get it lower. The diacetyl should clean up in time.

 

[bill_face]

Once it gets down to the 1.020 range and stops usually means it done, stalled ferments don't really happen in my eexperience and there isn't much you can do to get it lower. The diacetyl should clean up in time.

Usually i just wait until it stops bubbling, but this one isn't stopping... So i think it's still fermenting slowly

 

[Clint]

Out of curiosity,what's your grain bill?

 

[bill_face]

It was a recipe from a book called Brewing Classic Styles by Jamil Zainasheff. Pale Malt 2.15kg, Brown Malt 0.23kg, Crystal (32l) 0.23kg, Chocolate Malt 0.14kg (for a 11 lire brew)

I've haven't made this recipe or used this yeast before. In addition I had my first experiment with water chemistry using the results from Bristol Water for my area & this calculator: Liquor Treatment, or Knowing Your Anions

 

[Pennine]

Usually i just wait until it stops bubbling, but this one isn't stopping... So i think it's still fermenting slowly

Nottingham is a pretty quick fermenter, usually it's done in 4-5 days at those temps. Even at 15c Nottingham will work pretty quickly.

What was your mash temp?

 

[bill_face]

I do a brew in a bag. Mashed at 67C. Sparge at 75

 

[Berry454]

If you want fermentation to increase just simply increase the temperature by 2-3 degrees c.

So if I'm fermenting at 20c and it slows down. If I'm in a rush I'll increase it to 23c and things will speed up.

The speed of fermentation is greatly changed by temperature.

When things are nearly done but still fermenting I'll often increase the temperature. Because who wants to wait 3 weeks to move one point up a hydrometer?