Recurring Problem : High/Over Attenuation

[Luxo_Aussie]

G'day All,

I don't know if anyone else has had this problem, but all my latest beers are attenuating far too much regardless of yeast selected or rest times during step mash. The last 13 batches have had an average attenuation is sitting at 88% with the average FG is 1006. Style-wise this has been a mix of american, belgian, australian and german style beers.

This sort of attenuation might be expected when using WLP530, but I've had these figures when using this yeast along with wyeast 3638, WLP009, wyeast 1272, wyeast 1335 & wyeast 1056. Some batches had some added sugars but 150gr at most, most are malt-only.

Beersmith has under estimated the FG on these batches consistently by 4-7 points when compared to the measured FG. I've double checked readings with a Tilt and recently a new hydrometer so faulty equipment shouldn't be the issue. If the yeast strain & equipment isn't to blame then could it possible be due to my mash schedule?

Most of these batches have been a hockhurtz with an extra step in the middle; three rests from one in the low-mid 60s, one in mid-high 60s and final in the low 70s for a total of 60 mins (not including mash out). For example 20@63 | 25@66 | 71@15 for a light/dry beer and 15@64 | 20@67 | 25@72 for a more medium bodied beer. But these more 'medium' body mashes have still finished up around 1006 when done even when starting high (1050-1060).

There's a lot of content online about under-attenuation but not a lot when the opposite happens. Any ideas what I'm doing wrong here? Just keen for one beer to finish around 1010 for once! Any notes, advice or comments appreciated!

Cheers & Thanks!

 

[MHB]

Check your mash temperatures. Odds on you are actually mashing a couple of degrees cooler than you think you are. Beta Amylase is getting more of a run than planed and making more fermentable sugars.
Every brewer should have one good quality lab thermometer that you use as a reference.
mark

 

[kadmium]

G'day All,

I don't know if anyone else has had this problem, but all my latest beers are attenuating far too much regardless of yeast selected or rest times during step mash. The last 13 batches have had an average attenuation is sitting at 88% with the average FG is 1006. Style-wise this has been a mix of american, belgian, australian and german style beers.

This sort of attenuation might be expected when using WLP530, but I've had these figures when using this yeast along with wyeast 3638, WLP009, wyeast 1272, wyeast 1335 & wyeast 1056. Some batches had some added sugars but 150gr at most, most are malt-only.

Beersmith has under estimated the FG on these batches consistently by 4-7 points when compared to the measured FG. I've double checked readings with a Tilt and recently a new hydrometer so faulty equipment shouldn't be the issue. If the yeast strain & equipment isn't to blame then could it possible be due to my mash schedule?

Most of these batches have been a hockhurtz with an extra step in the middle; three rests from one in the low-mid 60s, one in mid-high 60s and final in the low 70s for a total of 60 mins (not including mash out). For example 20@63 | 25@66 | 71@15 for a light/dry beer and 15@64 | 20@67 | 25@72 for a more medium bodied beer. But these more 'medium' body mashes have still finished up around 1006 when done even when starting high (1050-1060).

There's a lot of content online about under-attenuation but not a lot when the opposite happens. Any ideas what I'm doing wrong here? Just keen for one beer to finish around 1010 for once! Any notes, advice or comments appreciated!

Cheers & Thanks!

Hey mate. The only thing I could suggest is perhaps eliminating the complicated mash process. With today's malts, most of the conversion is over in the first 20 minutes. So by doing the first step most of your conversion is over, and you will be getting a highly fermentable wort.

Not saying that it's wrong to do a 3 step mash, but I don't see the point tbh. Just a single step with a mashout is usually enough.

Do yourself a favour and do a conversion test next time, and do it after 15m, 20m etc to see when conversion is complete. You might be surprised.

I still do a 60minute mash because, well I just can't bring myself to mash for 30m and I've heard if you mash too quickly the beer under attenuates, opposite of your problem. The recommended short mash is around 40m so what's an extra 20 eh?

So, TLDR:
Try a single step mash with a mashout at 76. I'm guessing the low 70s is an alpha amylase step?

 

[butisitart]

i've gone to pretty much single temp mash, out of being an uncommitted brewer. so 63 or 65 or 68, sometimes with a 72 or 76 goodnight.
only real variation is a 42 bath for 15 mins if i'm loaded up with flaked barley. which i suspect gives the malt a good soak before it gets down to work, too. don't know if it's improved my beers, but it hasn't damaged them.
i did read somewhere once that a soak in the low 30s gets things going, but even if that's so, i expect you would need a pretty rapid ramp up to required mash temp. i'm sure there are valid views on that one LOL

 

[Luxo_Aussie]

Check your mash temperatures. Odds on you are actually mashing a couple of degrees cooler than you think you are. Beta Amylase is getting more of a run than planed and making more fermentable sugars.

I have double checked step temperatures, albiet without a lab thermometer. Will add this to the shopping list.

Do yourself a favour and do a conversion test next time, and do it after 15m, 20m etc to see when conversion is complete. You might be surprised.

Great idea - I'll give this a go and test the gravity at 5 minuite intervals on the next batch to see how long it actually takes. Might cut some time off my brewday.

I still do a 60minute mash because, well I just can't bring myself to mash for 30m and I've heard if you mash too quickly the beer under attenuates, opposite of your problem. The recommended short mash is around 40m so what's an extra 20 eh?

So, TLDR:
Try a single step mash with a mashout at 76. I'm guessing the low 70s is an alpha amylase step?

Correct. I think you're onto the root cause since (for example) a 15 minute rest around 63 would result the mash spending roughly 22 minutes in the beta amylase (60-65) range when including the deactivation of the pump every 10 minutes or so when the Braumeister is doing it's cycle. Might be an idea just to cut out this step for the next couple of brews (since they are full bodied styled) and gauge the results to see if the FG decides to rise.

only real variation is a 42 bath for 15 mins if i'm loaded up with flaked barley. which i suspect gives the malt a good soak before it gets down to work, too. don't know if it's improved my beers, but it hasn't damaged them.

I started doing a short 10 minute rest for beers which had a fair percentage of oats, wheat or flaked materials in the 48 degrees range & feel like that's been helping with efficiency/sparge on these sorts of batches. Happy to see I'm not the only one doing this rest. I was before this doing a protein rest at 55 on all batches but had a string with atrocious head retention so taken a permanent rest from using this rest.

Really appreciate the feedback, hopefully I can control the attenuation moving forward and leave something in the glass on future beers (aside from alcohol)

 

[MHB]

If you are brewing on a Braumeister, its worth remembering that the rate of rise is about 1oC/minute.
If you set up a mash regime like your first one (20@63 | 25@66 | 71@15 ) you are mashing for 60minutes plus the interval between 63 and 71, so another 8 minutes. Does mean you are spending longer at high B-Amylase activity temperatures than you think.
I tend to work out the rests I want and then subtract half of the rise time from each rest time (i.e. from 63-66 is only 3 degrees) I would be taking two minutes off the 63o rest and one off the bottom of the 66o rest (and another two or three off the top of 66o rest for the next rise).
With your steps being so close together it isn't going to matter much but if you are mashing in at say 45oC then ramping to 65o its adds 20 minutes. Remember that enzymes don't turn on and off like a light, they ramp up getting faster and faster until eventually they fall off a cliff and die (well denature). For quite a fair fraction of that 20 minutes your saccharifying enzymes are working, especially Beta Amylase.

We mash-out to end all enzyme activity, if you stop mashing at 71oC (which is pretty close to the Alpha peak) and pull out the malt pipe, the enzymes in the wort will still be working. They will keep chipping away at complex dextrins in the wort, making the wort more and more fermentable.
You really need to mash-out at 77-80oC to stop enzyme activity. I suspect this is playing a role in you problem.

One of my locals (Coalminer) has a BM that reads 2oC high all the time, he knows this and can allow for it. That's why I recommend every brewer have a decent thermometer (lab grade glass thermometer) that wont get flat batteries or suffer from corrosion or broken wires. Use this occasionally as a reference, can save you a pile of angst, especially those brewers relying on cheap dial thermometers, seen plenty of them out by well over 5oC (up to 10oC) and yes that will change your beer.
Mark

 

[Coalminer]

If you are brewing on a Braumeister, its worth remembering that the rate of rise is about 1oC/minute.
If you set up a mash regime like your first one (20@63 | 25@66 | 71@15 ) you are mashing for 60minutes plus the interval between 63 and 71, so another 8 minutes. Does mean you are spending longer at high B-Amylase activity temperatures than you think.
I tend to work out the rests I want and then subtract half of the rise time from each rest time (i.e. from 63-66 is only 3 degrees) I would be taking two minutes off the 63o rest and one off the bottom of the 66o rest (and another two or three off the top of 66o rest for the next rise).
With your steps being so close together it isn't going to matter much but if you are mashing in at say 45oC then ramping to 65o its adds 20 minutes. Remember that enzymes don't turn on and off like a light, they ramp up getting faster and faster until eventually they fall off a cliff and die (well denature). For quite a fair fraction of that 20 minutes your saccharifying enzymes are working, especially Beta Amylase.

We mash-out to end all enzyme activity, if you stop mashing at 71oC (which is pretty close to the Alpha peak) and pull out the malt pipe, the enzymes in the wort will still be working. They will keep chipping away at complex dextrins in the wort, making the wort more and more fermentable.
You really need to mash-out at 77-80oC to stop enzyme activity. I suspect this is playing a role in you problem.

One of my locals (Coalminer) has a BM that reads 2oC high all the time, he knows this and can allow for it. That's why I recommend every brewer have a decent thermometer (lab grade glass thermometer) that wont get flat batteries or suffer from corrosion or broken wires. Use this occasionally as a reference, can save you a pile of angst, especially those brewers relying on cheap dial thermometers, seen plenty of them out by well over 5oC (up to 10oC) and yes that will change your beer.
Mark

That error is now up to 4 minutes now, still easily allowed for, but must keep alert (no brain fades during schedule entering)

 

[kadmium]

Yeah, I have a guten and I know there is a 1c difference between bottom and top temp as well. 65 is 66 top, which is fine. Also, I am actually going to do a Mike Hockhurz Mash this weekend (first time) for a crack at a Czech Pilsner, cause why not?

Looks like i'm eating my words about being simple!

 

[MHB]

Hockhurz jump mash is really designed for hot water infusion, where near boiling water is introduced (usually underlet while stirring like buggery) to get the step up in a matter of minutes.
Really works best in a 2+V system. Baumeister and other 1V systems really don't get there fast enough. About 1oC/minute is as fast as you can get heat across a stainless surface without having the surfaces so hot (surface of elements included) that they are denaturing the enzymes close to the surfaces. Same applies to commercial systems with steam jacket heating on the floor and sided 1oC/m is about the limit even with the rakes going flat out.
The calculations for how much how hot water to add aren't all that complicated.

To check the temperature on a Braumeister I use a precision thermometer (0.1oC), put some water (say about 1/4-1/3 of nominal volume, run the heating and the pump in manual mode at about 65-70oC, give it time to stabilise, then take the reading. Partly because my precision thermometer goes from 40-70oC
The pump on the BM shuts down well under 100oC so just make sure you are testing while the pump is running so the water temperature is homogeneous.
Nice to note that the latest BM has a temperature offset/correction as part of the setup as well as a few other features that have been a long time coming, like a start at timer, can memorise a bunch programs... of very nice computer now.

 

[kadmium]

Yeah very happy with the Guten, I would say 1c a minute is about spot on. In that case, I will give the Hockhurz a miss, and go with a single step with Mash Out as per usual, but go with a lower mash. Probably around 63c?

Next time, I will do a decoction mash and see the difference.

 

[MHB]

Plan a looooooong brew day
M

 

[kadmium]

Nahhh, i'm gonna go Triple Decoction. Might do an overnighter hahahaha

 

[Luxo_Aussie]

So a bit of an update. Haven't had the thermometer delivered yet but I brewed a <sort of> Coopers ESVA (some changes to the recipe posted) with an updated mash schedule of 10@48 | 5@63 | 30@67 | 20@72 | 5@78 for 5.7kg of grains + coopers cultured yeast. I took a hydrometer reading at the middle of the 63 degree step - 1.042, which I'm guessing means that just the ramp had already converted a huge amount of the sugars. 21L of 1067 wort into the fermenter & after 10 days I've gotten to 1008 - probably close to the FG but was hoping for something a bit higher given the amount of fermentables. Tastes great, but not what I was looking for.

Next strategy is to simply remove all steps before 67 and see if that gives me something that finishes around 1010 OR I'm wondering if my dough-in at 40 degrees is the problem, perhaps the ramp is taking too long and I should just dough in at 63 or 67? I should test the timing of the ramp to see if it's 1 degree per second. Brewing a 4.5%-ish Tropical Pale Ale this week and keen for more of a body despite the lower starting gravity.

 

[kadmium]

Hey mate, so a couple of things to note - The majority of the conversion is completed within the first 30 minutes. The usual ramp time for a single vessel brew system is 1 degree per minute. so, 10 @ 48 plus a ramps of 15 is 25 minutes in the low range, then a further 5 @63 followed by a call it 5 min ramp. To be completely honest, I don't think if you brewed a single step mash with a Mash Out and a stepped mash with todays highly modified malts, on MOST brews, you would not tell the difference.

I really think there is something, other than perhaps Decoction mashing (just use melonodin malt) you would really tell. I would honestly cut down your brew day, and just start doing single step mashing for the target body. So, Light / Med / Full and their respective temps. I just recently did a Czech Pilsner and single stepped at 64 with a Mash Out.

If you're going for a thicker body, in the medium to medium/full range, mashing around 66 should see you there.

 

[butisitart]

i only go 40-41 degrees if i've got a load of flaked barley in there. i'm actually thinking of doing a flake rest separate from the main barley malt, on the stove, then adding that to the 63 or 68 when i'm loading the malt in. would be a certain amount of fiddling around, cos i'd want to add and mix the flake into the malt so it doesn't form a glutinous ball. would probably give a better mash result, but still thinking through the process and if it's worth the effort.
actually, with flakes it'll probably be a 68 malty, so 27 degree step. i might have to think about this a bit harder, cos that's a huge step-up

 

[MaggieO]

I imagine a bacterial infection could cause this. Especially as it started with no change in your equipment or process.

Could also be remnants of a diastaticus yeast used in a saison for example.

 

[kadmium]

Great idea - I'll give this a go and test the gravity at 5 minuite intervals on the next batch to see how long it actually takes. Might cut some time off my brewday.

Hey mate. Just re-read the thread to see if anything else I missed. To do a conversion test, use Iodine solution to check for starch converted fully. Essentially you want to use Iodine (betadine works fine) grab a few drops of wort with no grain in it, and put in a clean white bowl or plate.

Drop the iodine on it. If the liquid turns black/deep blue there is unconverted starch. If the liquid stays wort coloured and the iodine stays red/brown then conversion is completed.

Now, this doesn't mean the mash is over as the enzymes may still be breaking down the sugars, but I have found most of my mash to be converted within 30m.

Just a thought.