Quick question regarding fermentation if I may.

[treebeard]

Hi folks. Sorry for the questions but.... The primary fermentation is now complete after 5 days. I have fermented at 19 degrees during this time and all activity from the blow-off tube all but ceased. I have dumped the trub off now, a gravity reading shows it's down to 1.016 from 1.060, however, I have noticed that when my heat belt kicks in the bubbles from the blow-off begin again.

Should I be slowly raising the temp up by a couple of degrees for the rest of the time or just leave alone? The style of beer is American pale ale and my yeast is Safale US 05.

Any advice would be appreciated :)

 

[Sadfield]

I would, it won't do any harm. I calculate that as 73% attenuation, where as US-05 usually gives 80+, so it still has a little way to go yet. A slightly warmer temp will also aid extraction if you are dry hopping.

 

[foxbat]

It's OK to let it rise a few degrees - Fermentis explicity say that in their Tips & Tricks booklet that you can read online. They also say it's good to lower the temperature right at the end to assist flocculation (that's the 'cold crash' that lots of us do if we can).

 

[Simonh82]

The bubbles are likely to just be co2 coming out of solution as the temperature rises. Cold liquids can hold onto more dissolved gas at a lower temperature, so as they heat up, that gas escapes.

No harm in raising the temperature to 22°C.

 

[DoctorMick]

At 1.016 I’d be amazed if primary has finished, it’s just slowed down. Personally I’d just leave it alone but, as others have said, raising the temp a little won’t do any harm and will likely speed up the rest of fermentation.

 

[Slid]

Even from 1.060, US 05 is going to go down to much nearer 1.005. I would be very nervous about bottling below 1.010.

 

[Sadfield]

Even from 1.060, US 05 is going to go down to much nearer 1.005. I would be very nervous about bottling below 1.010.

1.005? Na. That's 91% attenuation, it's not a Saison yeast. And surely you'd be nervous bottling above 1.010 not below? ;-)

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[JapanBrew]

It might be close. 2 days before you cold crash it, you should raise the temp up a bit. This is called diacetyl rest. The yeast produce a lot of byproducts and diacetyl is the more profound one. When you raise the temp up a bit at the end of fermentation, this gets the yeast working again but there won’t be enough sugars so those little buggers will start absorbing their byproducts.
However, 5 days is a bit early in my opinion. But I wouldn’t know how that recipe usually ends up. Like the others said, that yeast can really eat up sugars. I’d wait till day 10 or so then raise the temp up 2 degrees. That’s just my advice.

 

[MickDundee]

Even from 1.060, US 05 is going to go down to much nearer 1.005. I would be very nervous about bottling below 1.010.

I’ve never had US-05 go below 1.010, and 1.052 is the highest SG I have had with it!

 

[treebeard]

Thanks for all the replies. It is very much appreciated :thumb:

From the advice I think my plan will be raise the temp from 19° to 22° over the next 4 days which from today would be day 10, take a gravity reading then leave it until day 14. Then at that point I intend to dry hop for a further 5 days so I'll let it cool during that period. Does the sound reasonable?

 

[treebeard]

Even from 1.060, US 05 is going to go down to much nearer 1.005. I would be very nervous about bottling below 1.010.

Thanks Slid. Yes me too! I would never risk bottling until I had three consecutive stable gravity readings at 14 days.

 

[Slid]

I’ve never had US-05 go below 1.010, and 1.052 is the highest SG I have had with it!

Interesting point. As far as the attenuation goes, here are my theories:

I usually use a new sachet of any yeast to give me 4-6 re-used trub bottles (250ml previously containing cheap lemonade). This means that most of the time, I am actually using a yeast that has come from a very healthy culture from an AG brew. Plus, 3 weeks in FV might be quite long for a HB'er?

Second theory is about my using 3 FV's for some time, using different yeasts, including Belgian yeasts like Mangrove Jack M31 and others. These have documented attenuation powers at well into the 90%'s. As Starsan leaves yeast cells and mainly kills bacteria, perhaps my cleansing and sanitation regime means that there are always enough super-attenuation yeast cells to "take over" at the end of my 2wk & 1wk regime in the FV's.

Third suggestion is that if there are indeed the yeast cells of previous brews in your brewing equipment, and these are different strains of yeast, then whether they are super-attenuating or not, the different yeasts may be able to convert slightly different mixes of fermentables and thus a mix of two or three different strains may be able to get down to a lower FG than any one in isolation.

Not sure what really is going on, but these are my thoughts.