Poor Attenuation

[Mr_Fez]

Hi I’m not sure if this is posting in the right place or not, so forgive me if it’s wrong.

I have twice brewed a nut brown ale that has twice started at 1.055 but had only achieved 1.030 even after four weeks.

Here is the recipe (BIAB keggle)
Pale malt 2 roe 4.1kg 74.9%
Caramel crystal malt 60L 0.50 kg 9.1%
Flake coats 0.50 kg 9.1%
Victory malt 0.25 kg 4.6%
Chocolate Malt 0.12 kg 2.3%

Fuggles 40g at 60 min
Goldings 30g at 15
1/2 whilfloc tablet 10min

Nottingham yeast 1pkt

Mashed in at 71c
Held for 90 min at 67c

I rehydrated the yeast and pitched at 20c, then kept in temp controlled fridge at 18c

Now I’m not sure of the problem, is my mash to long (I know 60min is the norm) and to high in temp to produce some unfermentable long chain sugars, or should I try 2 pkt of Nottingham?

I can’t help myself and I mix the mash around a bit though out the 90min.

My first batch I never got to taste as it fell on the floor and I lost the lot!
I ended up kegging the second batch, and it wasn’t bad, a little sweet and tacky but great flavour think it could be better.

I think this should be a great recipe, I just want to get better figures.

 

[MHB]

How sure of your mash temperature?
Mark

 

[Garagebrew]

I had the same issue with my first few beers, I got some great flavours but a lot of unfermentable sugars so the FG was staying high even though fermentation was complete. I lowered my mash temp from 68C to 65C which solved the issue and had my later beers FG reaching 1.010 or there abouts.
This worked for me but just keep in mind that my equipment may differ to yours and a lower mash temp will also lead to a dryer beer.
Hope this helps mate, good luck with the next brew.

 

[Mr_Fez]

How sure of your mash temperature?
Mark

I am fairly sure,
I have made the keggle with an in built thermometer, but with testing I don’t reply on it so much so I use s separate glass thermometer that I suspend into the keggle.
I watch the temp throughout the mash, and wrap the keggle in a blanket. On a cold day I may reignite the burner if I see the temp drop.
I think this might be my issue and I should just leave it alone.
I also tend to stir it a bit also, makes me feel more like the master of the magic going on. But I know that’s not true.

 

[Mr_Fez]

I had the same issue with my first few beers, I got some great flavours but a lot of unfermentable sugars so the FG was staying high even though fermentation was complete. I lowered my mash temp from 68C to 65C which solved the issue and had my later beers FG reaching 1.010 or there abouts.
This worked for me but just keep in mind that my equipment may differ to yours and a lower mash temp will also lead to a dryer beer.
Hope this helps mate, good luck with the next brew.

Thanks, Im fairly sue this is my issue, so it’s great to hear what you did and the results.
Cheers!

 

[scomet]

Good morning Mr Fez, what Mark and Gb say +
Nottingham should chew through a wort like that in a matter of days
First thing I would look at is yeast health, when rehydrating temperatures are critical so you dont shock the yeast, they say to rehydrate a couple of degrees higher than your wort 20/22c dont let the rehydrated yeast sit too long and also try a teaspoon of yeast nutrient.
+ & dont put cold dry yeast into warm water

Good luck - You’ll have it down to 1010 or less in no time :-}

 

[quadbox]

Calibrated that thermometer lately?

 

[Schikitar]

I also have similar problems with attenuation, usually bottoming out at around 1.018-1.020 instead of 1.010-1.014, I'm suspecting my thermometer - any good tips for calibration? Also, I think my hydrometer reads a couple points higher than it should, I need to look at that again (I only just remembered)!

 

[MHB]

Ok if your thermometer is accurate, you will get dryer beer (better attenuated) by dropping the mash temp a couple of degrees.

I have seen cheap glass thermometers that were 20oC out, even very good ones come in two types being Total and Partial Immersion, using a good one the wrong way can give you a couple of degrees error at mashing temperatures.

Do your self a favour and read the back of the thermometer,, it should say "Total Immersion", "76mm Immersion" or have a line 76mm from the bulb end. Make sure you are using it appropriately.

Total Immersion, Partial Immersion, what do these terms mean?
Mark

 

[Coalminer]

Follow pitching rates and rehydration method as per Lallemand instructions may help

http://www.lallemandbrewing.com/wp-content/uploads/2017/03/lallemand-tds-nottingham-021317-2.pdf

 

[hoppy2B]

I've started using a small electronic thermometer. I think it cost me just a bit over $20. It is pretty good. It will do stuff like boiling oil, which is a lot hotter than boiling wort etc. And it is easy to read and very durable. Worth what I payed for it.

 

[MHB]

I have lots of different thermometers use them for all sorts of different jobs. The problem with anything electronic (and a lot of bimetallic analogue to) is you have no way of knowing if they stay accurate! Batteries flatten, corrosion builds up on terminals, sugary wort gets in... and all of a sudden it isn't telling the truth and you have no way of knowing
Bit like a pH meter, mine isn't cheap arse bit of crap, but I still have to calibrate it regularly against reference standards, same with the Conductivity and Turbidity meters, if you don't calibrate you might as well just pull a random number out of your arse.
To my mind every brewer should have one good quality laboratory thermometer that they use as a reference. We are talking $15-20, I used to use a calibrated (NATA) thermometer to check every thermometer I sold, any observable error and they went back to the supplier.

Just keep thinking if you don't know, you are guessing.
Mark

 

[Mr_Fez]

I have lots of different thermometers use them for all sorts of different jobs. The problem with anything electronic (and a lot of bimetallic analogue to) is you have no way of knowing if they stay accurate! Batteries flatten, corrosion builds up on terminals, sugary wort gets in... and all of a sudden it isn't telling the truth and you have no way of knowing
Bit like a pH meter, mine isn't cheap arse bit of crap, but I still have to calibrate it regularly against reference standards, same with the Conductivity and Turbidity meters, if you don't calibrate you might as well just pull a random number out of your arse.
To my mind every brewer should have one good quality laboratory thermometer that they use as a reference. We are talking $15-20, I used to use a calibrated (NATA) thermometer to check every thermometer I sold, any observable error and they went back to the supplier.

Just keep thinking if you don't know, you are guessing.
Mark

Thanks for this Mark, I’m using a glass total immersion, but now have a better understanding in what that means. I never gave it a second thought to the differences in thermometers. I don’t use the electric ones,
Learning something every day.
So back to original problem, would you agree it could be temp related or a recipe issue or a yeast problem. I haven’t had these issues with my Kolsch, pale ale or IPA.

 

[Mr_Fez]

I have lots of different thermometers use them for all sorts of different jobs. The problem with anything electronic (and a lot of bimetallic analogue to) is you have no way of knowing if they stay accurate! Batteries flatten, corrosion builds up on terminals, sugary wort gets in... and all of a sudden it isn't telling the truth and you have no way of knowing
Bit like a pH meter, mine isn't cheap arse bit of crap, but I still have to calibrate it regularly against reference standards, same with the Conductivity and Turbidity meters, if you don't calibrate you might as well just pull a random number out of your arse.
To my mind every brewer should have one good quality laboratory thermometer that they use as a reference. We are talking $15-20, I used to use a calibrated (NATA) thermometer to check every thermometer I sold, any observable error and they went back to the supplier.

Just keep thinking if you don't know, you are guessing.
Mark

Thanks for this Mark, I’m using a glass total immersion, but now have a better understanding in what that means. I never gave it a second thought to the differences in thermometers. I don’t use the electric ones,
Learning something every day.
So back to original problem, would you agree it could be temp related or a recipe issue or a yeast problem. I haven’t had these issues with my Kolsch, pale ale or IPA.

 

[MHB]

Most likely to be mash temperature related, its also the easiest thing to check first.
I find I get good results with both Nottingham and Windsor when pitched at 1g/L, which is what they say on the packet.

Try the adjusted temperature, see if that fixes the problem, if yes all good, if not we will need to look elsewhere.
Your OP was pretty comprehensive, just missing batch size, assumed something in the 20-25L range from the grain bill and at that size one packet of yeast should do the job at 18oC.

Thermometers are a bit of a hobby (horse to) got glass thermometers that will cover the range from -200 to +400oC, mind you they don't get a lot of work at either end of the ranges.
Mark

 

[hoppy2B]

I have 3 thermometers for brewing actually. The new electronic one that I just had to mention because I thought it was so cool, a good glass one and a small dial one.

I agree that you need to cross reference your thermometers. It would be rare (if ever) that I didn't use at least 2 thermometers on a mash, just to be sure.

 

[quadbox]

But I mean if it's a problem with yeast viability or underpitching, you're still at 1.030... Nothing stopping you adding another pitch and seeing if it'll attenuate some more. Jack the temp up a couple of degrees to ~ 20C, add some more yeast, and see if it fixes the problem.

How much yeast did you pitch, what was the OG and the batch size? Did you rehydrate first (assuming dry yeast)?

Big difference between being stuck at 1.015 and being stuck at 1.030, the latter's clearly a problem somewhere

 

[scomet]

I also have similar problems with attenuation

This is a very interesting question you raise, 10 years ago I was where you are now.
3 years ago I was where Schikitar is.
My last English Bitter came down to 1002!! I had to check it thrice as I didn't believe it!!

English Bitter ‘Landlady’ is the standard beer in Triumph Brewings’ Tap Room, the recipe has barely changed over the years. 4Kg malt 500g sugar (in various forms) 110g Caramunich (123) 20g midnight wheat, fuggles, GEK, Styrian; but the process has.
Look at the recipes from this last one, to a 3 year, to a 7 year, all done on the Brau same mash temp 67c. What made the difference?? I thought it was BS anyone could get an ale sub 1010!!

Years ago I read that sanitation was the key to making great beer. Now; I dont even know where my ‘blow off tube’ is anymore!
Secondly yeast health, I over pitch Nottingham bought in bulk from Craft Brewer, good aeration hydration and sanitation I dont make starters, job done in under a week.
#3 correct temperatures, very important at certain stages but not #1 by a long shot making ales, imho…..
Or it could be the water or the phase of the * moon or…? It certainly changes the beer taste :-}

 

[dave_h]

How are you measuring the gravity? Assume you know if you are using a refractometer you need to adjust the value.

 

[gaijin]

Sounds like this has been solved - temp or yeast related. It sounds like this isn't your first one or two brews, but just in case... you don't live in an area with really hard water do you?

I recently brewed a black lager and forgot to add chalk to the mash. The FG only dropped to 1.17 where it usually gets down to about 1.008. This meant that the mash pH was around 4.9 or 5.0 and it didn't do a full conversion. It ended a little sweet with a heap of body. I'm in Brisbane so we have a water profile which works for all but beers with heaps of dark/roasted grain.