Stuck Fermentation? - thoughts

[Needle99]

Hi All,

Fairly new to fermenting beer (doing batch #4).

Brewing a Russian Imperial Stout FWK. Was supposed to be OG around 1.090. Measured 16.1 Brix (1.060) using a refractometer (after I added 6L water to the 15L FWK).
Yeast is 2 x packets of Mangrove Jacks M42 Strong Ale that was rehydrated and pitched into 20C wort, which was then cooled to 18C for fermentation in a temp controlled fermentation fridge.

First time using a blow off tube, had a little mishap where the pressure caused the hole in the milk bottle that the tubing went in to seal up around the tube.
This caused the top or the Mangrove Jacks Craft series Fermenter to pop up spewing some wort/krausen as the pressure released. Luckily it appears to have only happened fairly early in the process (I found it at about the 38hr mark)
I removed the top from the milk bottle and the the CO2 caused massive amounts of foaming and everything then appeared normal for the next 3-4 days.

Using the refractometer Gravity has only dropped down to 7.2 Brix (1.030) and has been steady for the last 2 days. I have increased temp to 20C and shaken the fermenter a little (without too much sloshing to add too much oxygen) to try to rouse the yeast to complete fermentation.

What are peoples thoughts on best action here?
Leave for a little while longer and see if it changes? (assuming a slow fermentation is still happening)
Leave and bottle at 1030 (would be risky I think)
Grab another packet of yeast and add? (should I try to make my first starter if so, given it is nearing end of fermentation?)

Edited to fix incorrect terminology - Plato/Brix

 

[mtb]

Refractometer readings get offset with the presence of alcohol. Warra48 posted a chart somewhere already, but here it is again.
Given your reported OG, it appears your brew has finished at ~1.010.

 

[mtb]

..it's also a bit strange that your expected OG was 1.090 from a FWK, but after following the instructions, you hit 30 points lower. If you indeed followed the FWK instructions, I'd say the water wasn't blended in properly and you took a reading from a more watery portion of the wort. Assume you actually had an OG of 1.090 in that case - and another chart is necessary to calculate the refractometer offset

 

[goatchop41]

..it's also a bit strange that your expected OG was 1.090 from a FWK, but after following the instructions, you hit 30 points lower. If you indeed followed the FWK instructions, I'd say the water wasn't blended in properly and you took a reading from a more watery portion of the wort. Assume you actually had an OG of 1.090 in that case - and another chart is necessary to calculate the refractometer offset

Don't stuff around with charts and shite. Just use an online calculator.

 

[goatchop41]

Hi All,

Fairly new to fermenting beer (doing batch #4).

Brewing a Russian Imperial Stout FWK. Was supposed to be OG around 1.090. Measured 15.1 Plato (1.060) using a refractometer (after I added 6L water to the 15L FWK).
Yeast is 2 x packets of Mangrove Jacks M42 Strong Ale that was rehydrated and pitched into 20C wort, which was then cooled to 18C for fermentation in a temp controlled fermentation fridge.

First time using a blow off tube, had a little mishap where the pressure caused the hole in the milk bottle that the tubing went in to seal up around the tube.
This caused the top or the Mangrove Jacks Craft series Fermenter to pop up spewing some wort/krausen as the pressure released. Luckily it appears to have only happened fairly early in the process (I found it at about the 38hr mark)
I removed the top from the milk bottle and the the CO2 caused massive amounts of foaming and everything then appeared normal for the next 3-4 days.

Using the refractometer Gravity has only dropped down to 7.2 plato (1.030) and has been steady for the last 2 days. I have increased temp to 20C and shaken the fermenter a little (without too much sloshing to add too much oxygen) to try to rouse the yeast to complete fermentation.

What are peoples thoughts on best action here?
Leave for a little while longer and see if it changes? (assuming a slow fermentation is still happening)
Leave and bottle at 1030 (would be risky I think)
Grab another packet of yeast and add? (should I try to make my first starter if so, given it is nearing end of fermentation?)

I'm not sure why on earth you're using plato and SG measurements when you're using a refractometer which measure in Brix...

Anyway, if we trust the reading of 7.2 plato and plug it in to an online calculator, we get a corrected SG of either:
A) 1.014 (with the OG entered as 1.060 - for the record, I agree with mtb's thought that this may be off. Provided that you followed the FWK instructions regarding volumes, then your OG should be exactly what they say it should be. In saying that diluting 15L of 1.090 to 21L gives an OG of 1.064, so if there weren't instructions to dilute, then that may be your OG and give an SG of 1.013)
or
B) 1.002!! (with an OG of 1.090)

Getting an RIS down to 1.002 from 1.090 is nigh on impossible without an infection, so I'm guessing that your OG was about 1.064 and your SG is now 1.013 (ABV 6.69%).
Let your temp slowly rise to 24oC (don't worry, you're way past the point of causing any off-flavours, that temp will just help it finish off) and see if you can bump a couple more points off. You're almost done (just not going to get to RIS-appropriate ABV levels)

 

[Needle99]

Ooops my bad. I did type plato and was talking Brix as that is what the measurement was....
Multitasking at work while worrying about my beer is a bad idea.....

The FWK instructions are very generic - and say for Kegging - dilute to 20L and for bottling dilute to 23L.
I am bottling and went 21L as being slightly under full RIS % is no biggie for me, I am brewing for flavour rather than alcohol hit.

When I bought the FWK a few weeks back, when discussing yeast 1.090 was mentioned. So that may or may not be diluted.

Based on the above responses I am guessing that was undiluted.

Thanks all for the feedback, I will take the worry hat off, and think of it more as a flavourfull stout than a RIS.

 

[Needle99]

I will put this down to not really knowing what I am doing. Learning as I go.....
I just double checked the spreadsheet where I recorded.
It was actually 16.1 Brix and now reads 7.2 brix (although sometimes it looks like 7.5 Brix) so some natural variation...

Using the calculators it looks like it has ended up around 7%.

I will still ramp up the temp to 24C over the next few days before Cold crashing.....
Be good to get bottled soon, as it will free the fermenter for a collab AG Porter brew on the weekend...

 

[Schikitar]

I think the fourth brew I tried to make was a RIS, really wish I didn't, lost a lot of hair!

 

[Tony121]

Multitasking at work while worrying about my beer is a bad idea.....

No, no it is not

 

[MHB]

Leaving aside the use of a refractometer to measure after the start of the ferment.
Your start gravity was 16.1 Brix (about the same as Plato at this level of accuracy) that is actually 1.0644, being made up of 15 L made up of "Fresh Wort Kit" and 6L of water, if you look at the good old C1V1=C2V2 and plug in the info, 21*16.1=15*C2 338.1/15=22.54oP (well Brix on your refract) that is an OG of ~1.090
Clearly to make a RIS with the FWK you shouldn't have added that 6L of water.

In your post from yesterday you say its at 7%, that means that (from ABV=Change in Gravity/7.5) 7*7.5=52.5 Points of change, from the OG of 1.060 means you should be down to 1.0075 and have an apparent attenuation of 87.5%.
It's finished, I doubt you need to screw around changing the temperature or anything else, crash chill if that's your want and get it into bottles or a keg....Enjoy, no RIS but probably going to be tasty.
Mark

 

[Coodgee]

If I was prime minister I would pass a law requiring refractometers to come with a warning about correcting for alcohol before they can be sold. It gets everyone, including me back in the day.

 

[goatchop41]

In your post from yesterday you say its at 7%, that means that (from ABV=Change in Gravity/7.5) 7*7.5=52.5 Points of change, from the OG of 1.060 means you should be down to 1.0075 and have an apparent attenuation of 87.5%.
It's finished, I doubt you need to screw around changing the temperature or anything else, crash chill if that's your want and get it into bottles or a keg....Enjoy, no RIS but probably going to be tasty.
Mark

He has said that he went from 16.1 Brix to about 7.5 - which is 1.066 down to 1.012. That's still an impressive 81% attenuation.
From reading the first post, it seems that this has only been in the fermenter for about a week...I'm all for getting a quick, clean ferment, then in to the keg, but wouldn't you think that a 1.066 OG beer would benefit from a few days at a higher temp? At the very least for a VDK rest

 

[MHB]

Are we doing diacetyl rests on Ales now? It really shouldn't be necessary, especially as he pitched two packs of ale yeast at 20oC.
He also said that after using a calculator the alcohol content was ~7%, that means a change as above, I goofed and put in 1.060 instead of 1.0644, so your right its about 81% apparent.
Still think is all over and can be packaged - fermentation can easily be over in three days with a good big healthy yeast dose.
Mark

 

[Needle99]

Thanks for the continued feedback.

Brew was put down on the 31st and I think was done between the 3rd and 5th. The M42 yeast is a beast. The 2 x packets were used thinking that it was going to end up being a 1.090 RIS, rather than a 1.066 stout . I usually do not really check the gravity for a week.
Was probably an overpitch due to OG being a lot lower than I expected. Assumptions are such a bad idea.

Slowly learning through research reading and trial and error.

Was originally fermented at 18C and then when I thought it was stuck I tried to rouse the yeast and increased the temp to 20C. I did end up with a couple of days at 22C, before starting the Cold Crash cool-down this morning. I plan on bottling Friday night to make the fermenter available for Saturdays' Porter Brew Day.
Originally was going to leave on the yeast cake longer to allow as much cleanup by the yeast as possible. But I ended up starting this 2 weeks after planned.

I should have been updating the brew spreadsheet the LBHS supplied me with the refractometer. It does have workings for the allowance of alcohol and Brix - to SG conversions built in.
Due to the near explosion of the blow off bottle managing to get sealed up I was worrying more than I should. All learning for process. Just need to stay on program
Was really not expecting it to complete so quickly based on all the threads I had seen with RIS issues. Was a 50/50 to try this at this stage or not. As it turns out am just doing a stout (after dilution) - so all is normal.
Tasted not too bad from the sample this morning. Will be very interesting to see what it tastes like when carbed and starting to mellow in a months time.