Burned my last beer--why?

[danb35]

I've brewed about a dozen beers on this system from brewhardware.com:
https://www.brewhardware.com/product_p/biabpackagepremium.htm
No real problems until the last batch, brewed last week, which was to be a Belgian Quad following this recipe:
https://shop.theelectricbrewery.com/pages/belgian-dark-strong-ale-quadrupel
...scaled using Brewfather to a 5.5 gal batch size, account for my boil-off, etc.

I noticed by the start of the boil that the wort was darker than I'd expected, given that I'd used only Pilsner malt (Briess, if it matters). At some point during the boil, I noticed an off smell which I didn't at the time identify as burning/scorching, but now suspect that's what it was. And once I transferred my wort to the fermenter and went to clean the kettle, I noticed a lot of burned-on residue on the heating element. And then a gravity sample taken this afternoon smells definitely burnt.

I don't want to dump the beer, but that probably isn't avoidable. But more than that, I want to figure out what happened so I can keep it from happening again. A few maybe-relevant observations:

• The grain bill consisted of just under 20 lb of Pilsner malt in 10 gal of water.
• I double-milled the grain, first at 0.045" and then at 0.020", the same as I've done with the last several batches without issue.
• Recirculation was on throughout the mash, including the "whirlpool" surrounding the heating element.
• This recipe calls for a protein rest at 131°F, which I don't ordinarily use.
  • The wort looked distinctly cloudy during this step, but was light in color.
• This is the first recipe where I've used significant amounts of Pilsner malt.
• Efficiency was lower than expected, even compared to my last brew, a clone of Sam Adams Double Bock with a pre-boil gravity of 1.075, which had a mash efficiency of 73%. This recipe expected a pre-boil gravity of 1.065, and had a mash efficiency of 67%.
• Mash pH was within a few points of expected at 5.54.

What would explain the burning, so I can avoid it in future batches?

 

[tracer bullet]

Issue with the heater itself? Too fine a grain grind, lots of powder on the bottom got burnt and only recirculated what was above it? Even if this was done before, maybe there was a different ingredient involved this time or something else changed like the flow rate or even the direction it pointed?

 

[Whisky River]

The recipe says to use 5.5lbs of “Belgian candi syrup” added very slowly. Is it possible you added it too quickly and it didn’t fully dissolve? Adding sugars is a notorious way to get scorching if you aren’t careful as they tend not to dissolve as quickly and throughly as you might expect and then settle on your kettle bottom or elements. Adding to the risk of scorching is the fact that your system seems to have the element directly in the wort. I would think that would be an invitation for scorching if anything were to settle near or contact the element.

 

[mashdar]

I always turn off the heat source and pour the candi-sugar through a hop spider or similar (edit: stirring vigorously and moving the spider up/down/around). I scorched LME early in my brewing adventures and have been paranoid ever since.

 

[tracer bullet]

I used a 1/2 pound ivert syrup in my electric Anil AIO and yep I did the same, turned the heat off while I poured. Old habits, that came about for a good reason.

 

[danb35]

I suspected the syrup, but that's added near the end of the boil--it wouldn't explain darkened wort at the beginning of the boil, would it?

 

[mashdar]

I suspected the syrup, but that's added near the end of the boil--it wouldn't explain darkened wort at the beginning of the boil, would it?

Does the element visually look ok? No narrow spots?

 

[danb35]

Does the element visually look ok?

Other than all the burned-on residue (I've managed to clean most, but not all, of it off), yes--no apparent damage to the surface, and it appears to be a constant diameter from end to end.

 

[MikeCo]

I have a similar system. All I can think of is the the wort was not properly being stirred and recirculated at some point during the mash and the element burned the grain. Maybe some unbroken dough clumps?

 

[mashdar]

I have a similar system. All I can think of is the the wort was not properly being stirred and recirculated at some point during the mash and the element burned the grain. Maybe some unbroken dough clumps?

I believe the system OP references is BIAB with the bag on top of a ~1cm wire screen, with burner below. Unless the bag somehow got down towards the element (?), the element should be in liquid only.

 

[danb35]

Mashdar, that's correct. The bag sits on the false bottom, which keeps it off the element by an inch or more. The pump is circulating wort in that space (as well as sending a little bit over the top) from the start of the mash until after mash out at around 185°F, whereupon (following Bobby's recommendations) it's turned off.

 

[mashdar]

I still think the most likely scorching was the syrup. Maybe the darkening before adding it is either something else, or your brain trying to retcon? (Brains are powerful post-hoc pattern/narative engines. Can't trust those things.)

 

[danb35]

I can definitely see the logic in that. I'm not sure I'm sold, but I can easily understand how it would look like a culprit, and it's easy enough to modify the process to avoid that as a problem--just add it after flameout, with the recirc pump running.

I recall seeing a video on YT (I think it was The Apartment Brewer, but I'm not certain) which incorporated a low-temp rest--I think it was a ferulic acid rest rather than protein rest, but I'm not certain there--and he was very cautious raising the temp from there, with concerns for scorching. IIRC, he raised it by adding boiling or near-boiling water to the wort to get it at least close to the next target temp, and then was fine heating it from there using his temp controller/heating element. Combining that vague memory with the cloudy wort during the protein rest still has me wondering if that's also a factor.

Edit: found the video: And it was a ferulic acid rest at 113°F, adding boiling water to raise the temp to a beta rest at 135°F; from there further adjustments were made using the controller/heating element. My protein rest was at 131°F, pretty near his beta rest, which calls my hypothesis further into question.

 

[mashdar]

Oh. I missed the protein rest. You can absolutely get insoluable starch at those temperatures that could hypothetically scorch. Whirlpooling the bottom moght keep it suspended, or might stack it up into the element. Do you usually do a protein rest?

 

[danb35]

No, I don't. I included it as it was part of the recipe, but I more often do single infusion.

 

[mashdar]

No, I don't. I included it as it was part of the recipe, but I more often do single infusion.

Here's a 2012 thread where a bunch of people weighed in with similar issues. protein rest causing scorched element

(edit: not sure why I thought 2012=2020)

 

[danb35]

Interesting, and thanks for the pointer. I don't see a solution there (other than "don't use a protein rest"), but at least it seems to corroborate that as a possible cause. And there was some off-white "gunk", for lack of a better word, on the outside of the bag.

 

[IDMaynard]

Didn't read ever response, but did you have the element on when you added the candi sugar? That could have caused some scorching.

 

[mashdar]

Didn't read ever response, but did you have the element on when you added the candi sugar? That could have caused some scorching.

He said he thinks something was off during boil (pre-syrup) and was wondering about the protein rest he did.

 

[passedpawn]

The folded-back ripple elements can trap particles (hops, grain, LME) between them. I suggest unbending the fold so that there is no trap there. The ripples I used were very bendable. I had the incoloy elements (dark gray) - not sure about SS if that's what you have.

I've brewed electric for a long time. I've definitely had a few smokey batches when stuff collected in there and burned.

 

[Bobby_M]

You didn't mention the "rate" at which you recirculate over the top of the grain. My SOP on this system says it should be limited to 2 qts per minute max and the rest should go through the whirlpool port.

Set whirlpool and recirculation flow rates. The whirlpool valve should remain full open for the entire mash. Turn the pump back on. Lift the lid enough to be able to see the opening of the Locline and slowly open the recirculation valve until the wort trickling out forms a diameter of approximately ⅜”. If you want to be more exact and get acclimated to what the correct flow looks like, collect the flow into a measuring cup and set the valve so that you fill to 1 cup in 10 to 15 seconds. If it’s less than 10 seconds, the flow rate is too high and you may run the wort into the bag faster than it can run through and you may damage your element. If it’s slower than 15 seconds, you may have trouble with lower mash temps at the very top of the mash. Once you are happy with the flow rate, put the lid back on the kettle. You will quickly learn visually what the proper flow rate is after a couple batches of measuring/timing.

The other thing to look at is the porosity of the bag. Organic soil and beer stone can eventually start constricting the openings of the bag over the course of a dozen batches. It should be soaked in hot PBW after each brewing session for about 30 minutes and rinsed aggressively with hot water. Pick a longer cycle, say 10-12 batches, to do a hot water and double strength starsan soak for about 30 minutes to break any beer stone down. Same aggressive rinse after.

Finally I do think the candi syrup can be an issue. Generally any syrup, dme, sugar addition should be done outside of the kettle. Drain about a gallon of wort into a bucket, stir the syrup into that really well and pour it back in to the boil. I'd do that in 1-2 pound increments if you have a bigger amount to add.


For what it's worth, I step mash more often than not and I don't have any issues with scorching but I do all those things above also...

 

[danb35]

I'll admit I haven't measured it, but around 3/8" diameter is about what I had, and is consistent with prior batches. My normal cleaning regimen for the bag has been to run it through the wash.

I used 2 lb of the candi syrup in this batch.

 

[Bobby_M]

I'll admit I haven't measured it, but around 3/8" diameter is about what I had, and is consistent with prior batches. My normal cleaning regimen for the bag has been to run it through the wash.

I used 2 lb of the candi syrup in this batch.

I don't know if the wash is aggressive enough, nor whether you use fabric softener (and/or if that's something that could clog it).

 

[danb35]

nor whether you use fabric softener

I don't for the bag (I use dryer sheets in some loads, but I air-dry the bag). All I can say otherwise is that it comes out looking clean. I haven't tried a hot PBW solution to clean it, but that'd be easy enough; that's what I use to clean the kettle with anyway.

 

[Alan Reginato]

A side question, does this burnt flavours tastes like rauchbier?
I'm asking, because I got the same problem last batch, started to heating at a low temperature and scorched the starch residue.

 

[danb35]

A side question, does this burnt flavours tastes like rauchbier?

Funny, a friend of mine helped me with this beer, and that was his response when I told him it had burned: "Rauchbier!" But sadly they don't; "smoked" smells very different from "burnt."

 

[cvbrewer]

I agree with an earlier post on the need to PBW soak the bag. I started originally with a 400 micron rating and thought it carried over some particles I didnt want. I then bought a 200 micron bag and liked the results. After about 8 batches I had an incident which I didnt watch closely enough. What happened is that during my mash recirculation the element was ran dry and I later reflected that the volume in my bag increased - creating an air space under the bag. The element had some signs of dry fire and after a conversation with brewhardware that was my culprit. I had to switch back to my bigger bag and pbw it after each brew. The pores get clogged and you really cant see it.

 

[danb35]

Took a second crack at this one today. Everything was as identical to last time as I could make it, except (1) bumped up the grain by about a pound to hit my target gravity, and (2) skipped the protein rest. No scorched smell or color, and came in just a touch higher on the OG than I'd planned. But did it ever foam up at the beginning of the boil! The boil volume was a little under 9 gallons, and the foam hit 14. Good thing I have a 15-gal kettle.

 

[Biggz1313]

I think @cvbrewer hit the nail on the head. I know you said you recirculate above and below the mash, but I'd bet you ran low on water volume in the bottom and the element was exposed. Not only does the element get exposed, so does the temp probe in those spike kettles so you will get an artificially low temp and the element will kick on 100% to bring that temp back up. It happened to me once when doing the same method you described above and was one of the main factors in my decision to buy a stainless mess basket for my kettle instead of continuing with the bag and false bottom. I would chalk this brew up as a loss and just learn from that mistake.

I bought a stainless steel straight edge ruler that I use to measure the height of the wort level during the mash. let it rest in the mash for the first ten minutes to make sure that the wort is making it's way through the mash at a good enough rate and not just getting stuck on top of the grains before I think about walking away. If I walk away from the mash for any amount of time, I'll note the level before I leave and the first thing I do upon return is check to make sure it's not super high and my element is sitting exposed under the basket.

 

[danb35]

but I'd bet you ran low on water volume in the bottom and the element was exposed.

I can't say for certain, of course, but I really don't think this is what happened--but it definitely points out the importance of not trying to recirculate over the top too quickly. And also of checking the level (my kettle has etched volume markings on the inside) to make sure it isn't increasing, which would indicate this is happening.

 

[Biggz1313]

I can't say for certain, of course, but I really don't think this is what happened--but it definitely points out the importance of not trying to recirculate over the top too quickly. And also of checking the level (my kettle has etched volume markings on the inside) to make sure it isn't increasing, which would indicate this is happening.

So I have the same spike kettle and was never able to see the markings through the bag, and now that I have the stainless mesh basket I can't see them at all. You're able to see the markings through your bag?

 

[Biggz1313]

The folded-back ripple elements can trap particles (hops, grain, LME) between them. I suggest unbending the fold so that there is no trap there. The ripples I used were very bendable. I had the incoloy elements (dark gray) - not sure about SS if that's what you have.

I've brewed electric for a long time. I've definitely had a few smokey batches when stuff collected in there and burned.

I have to ask at what point of the brew process was stuff able to collect between the element folds? I've brewed probably 60+ batches on mine so far and I just can see a part of the brew process where stuff could collect and sit between the element folds AND the element be on constantly and hot enough that it could burn something. The only part of my process where anything comes remotely close to building up and touching the element is during my chilling cycle where I'm recirculating wort through my CFC and back into the kettle (element is obviously off at this point). After chilled, I let it sit for 10-15 minutes to allow all the big stuff to fall out of solution/settle on the bottom before finally racking pretty clear wort to the fermenter. When I'm done racking there is most definitely stuff settled on and around the element, but for that whole process the element is off so I'm failing to see where what you're saying is even possible.

 

[danb35]

You're able to see the markings through your bag?

I haven't actually checked; I was just expecting I could. I'll have to check next time I brew.

 

[passedpawn]

I have to ask at what point of the brew process was stuff able to collect between the element folds?

It's possible I'm not understanding your comment, but I'll do my best here.

If any solid material is added to the boil kettle while the elements are on, that solid material could settle into the folds of the element.

If the hop sack that is hanging in there sits on the elements, it can burn during the boil.

Anyone who has brewed with an electrical element know that "gunk" collects on the element. If that gunk gets thick enough, it can burn. For this reason, I'd advise to look at them if you're doing back-to-back brewing sessions without cleaning between.

 

[Biggz1313]

It's possible I'm not understanding your comment, but I'll do my best here.

If any solid material is added to the boil kettle while the elements are on, that solid material could settle into the folds of the element.

If the hop sack that is hanging in there sits on the elements, it can burn during the boil.

Anyone who has brewed with an electrical element know that "gunk" collects on the element. If that gunk gets thick enough, it can burn. For this reason, I'd advise to look at them if you're doing back-to-back brewing sessions without cleaning between.

I don't use hop bags and use a stainless mesh basket for mashing. I've done many back to back batches and even with a thin layer of whatever is on the element, I've never had scotching ever. Maybe my stainless ripple makes the difference, I don't know, I'm just saying if there's liquid in the kettle and it's covering the element, I've never had it scotch ever. Again, anecdotal evidence but at least 10 back to back batches and a total of at least 60 batches is my sample size. Maybe if I got 3 or 4 batches with out cleaning something might happen, but that's the Brewers fault, not the element.

 

[passedpawn]

From an IPA I made. You can see where the ripple element (Camco 2963 ULWD) did a job on it. The bag o' hops smothered the element such that the water in the kettle didn't remove the heat fast enough. Can happen in other scenarios.