Slow - or stuck? - fermentation

[dennisdk2000]

Well, my beers are fermenting, but VERY slowly. Been thinking I should move them to somewhere warmer, or get some sort of heater sorted for them? Also read that stirring is an option. If it add heat one wa or the other, should I still stir? Should I stir before bothering with putting them somewhere warmer? I brewed on Tuesday, both demijohns started off nicely, but they are sat in a fairly cool place, one with Nottingham yeast, the other with Safbrew S-33.
Help! :?

Dennis

 

[bobsbeer]

I would give them a good stir. If you can just swirl the fermenter rather than open it and stir with a paddle. But your problem is probably the low temp.

 

[jonnymorris]

What temp are they at?

 

[dennisdk2000]

I forgot to get some of those stick-on thermometers, so not sure about the temperature, will get a thermometer out and check.

Dennis

 

[dennisdk2000]

Put a thermometer in a glass of water and placed it next to the demijohns. It now reads 17C. I used Safbrew S-33 for the Tripel, the ideal fermentation temperature for which is 15C-24C, and Nottingham for the Chocolate Maple Porter, the ideal fermentation temperature for which is 14C-21C. I've given them both a good swirl a couple hours ago. Now I'm getting nervous. :pray:

Dennis

 

[graysalchemy]

Have you taken any gravity readings to see how far they have gone ?

 

[dennisdk2000]

Not taken any gravity readings yet, didn't want to start messing about until I need to. If the time has come I will, just worried about infection, so keeping messing to a minimum!

Dennis

 

[dennisdk2000]

Just a little extra info on each brew:

Chocolate Maple Porter:
OG: 1.058
Yeast: Nottingham
Fermentation range: 14C-21C
Fermented steadily for the first couple days
Half of a 11g packet pitched to one demijohn after I re-hydrated as per packet instructions

Tripel:
OG: 1.076
Yeast: Safbrew S-33
Fermentation range: 15C-24C
Fermented like mad for the first day or two
Half of a 11.5g packet pitched to one demijohn after I re-hydrated as per packet instructions

Are they really done already? Sat at 17C at the moment, may have been cooler at some points...

Dennis

 

[RobWalker]

it's entirely likely. brews can finish in a few days. i've had one finish basically overnight with a good starter!

take your readings, dont worry about infections :

 

[dennisdk2000]

Finally managed to get some gravity readings:

The Chocolate Maple Porter is at 1.014, tasting somewhat drier than I expected and with less body/mouthfeel. This could be due to the fact that I struggled to keep the temperature up during the mash.

The Tripel is at 1.018, which made alarmbells ring (the dreaded 1.020 stuck fermentation). It tastes a lot sweeter than the porter (no surprise with the higher gravity reading), but for this beer I managed to keep the mash temperature up.

I noticed that when I brought the porter into the kitchen to check the gravity that there seemed to be renewed activity in the airlock, probably due to the kitchen being a lot warmer than the room the beers have been sat in. I'm thinking that maybe I should invest in a heater tray...

What do the experts think?

Dennis

 

[Farmbrew]

The trippel can be left longer - there's less risk of infection as it's got a whack fo alcohol already...if you can leave it somewhere warmer that would speed the last crawl in to your final gravity.

When you rack the beers off to the secondary you may find some increased activity and this can reduce the Grav by a point or two.

F

 

[dennisdk2000]

Cheers Farmbrew. Wasn't going to do a secondary fermentation, just bottle, leave for two weeks at "fermentation temperature" to carbonate, and the leave them cold for quite a few weeks to condition... Would you recommend I rack them to another FV for secondary fermentation before bottling?

Dennis

 

[Farmbrew]

I think you should be okay with the porter as it's nearly at FG. Somewhere between 1.009 and 1.012.

I think you'll have to be a bit patient with the Trippel. If you can work out the predicted FG (there are calcs for this) that would help you decide when to bottle.

 

[dennisdk2000]

I don't mind giving the porter a few more days in a slightly warmer location. As for the Tripel - should I stir it or just leave it alone? Will move that one to a warmer location too, I think.

Dennis

 

[dennisdk2000]

If you can work out the predicted FG (there are calcs for this) that would help you decide when to bottle.

Where will I find one of these? I'm sure I messed about with one at some point, but no idea where I came across it...

Dennis

 

[Farmbrew]

Where will I find one of these? I'm sure I messed about with one at some point, but no idea where I came across it...

Dennis

How's this?

http://www.homebrewtalk.com/f13/estimate-final-gravity-32826/

Just googled it quickly...Check spec of yeast you are using. This is a simple check - the FG (which is some ratio of the Terminal grav) depends on a yeast nutrient levels, fermentation temp and the amount of simple sugars in the wort (driven by mash conditions) amongst other things. Hope this helps.

Actually, there's a calc on here see top LHS of screen for the button...THBF think of everything!

 

[dennisdk2000]

Farmbrew - that's a lot simpler than the ones I found! Cheers, just got to find the attennuations for the yeasts I used and have a quick check...

Dennis

 

[dennisdk2000]

Just crunched the numbers. Based on the assumption that both yeast strains (Nottingham and Safbrew S-33) have high apparent attenuation as described by John Palmer in How To Brew (76-80%), the estimated FGs for my beers are:

For the Chocolate Maple Porter:
FG[estimated]=1.012-1.014
I measured a gravity of 1.014 on 03/05/12 and there seems to be very little to no activity in the airlock.
This would give an ABV of 5.8%, somewhat short of the 6.5% predicted by the recipe - not that I'm complaining!

For the Tripel:
FG[estimated]=1.015-1.018
I measured a gravity of 1.018 on 03/05/12 and there seems to be very little to no activity in the airlock. Did taste quite sweet though... The ABV for this beer would be 7.7% - again short of the 9.9% predicted by the recipe, and short of being a Tripel, more like a Two-And-A-Half...!

So I guess they're done? 76% apparent attenuation - is that reasonable for these strains? I've seen someone mention 85-90% for Nottingham...

Dennis

 

[Farmbrew]

Dennis

Just crunched the numbers. Based on the assumption that both yeast strains (Nottingham and Safbrew S-33) have high apparent attenuation as described by John Palmer in How To Brew (76-80%)

That S-33 % attenuation number seems high compared to http://www.highgravitybrew.com/BeerYeastChart-attenuation.html

Not sure if anybody else has experience of that particular yeast?

F

 

[dennisdk2000]

Dennis

Just crunched the numbers. Based on the assumption that both yeast strains (Nottingham and Safbrew S-33) have high apparent attenuation as described by John Palmer in How To Brew (76-80%)

That S-33 % attenuation number seems high compared to http://www.highgravitybrew.com/BeerYeastChart-attenuation.html

Not sure if anybody else has experience of that particular yeast?

F

:wha: According to that table, both Nottingham and S-33 have high attenuation... But I couldn't find their definition of that term.

Dennis