Gel like layer floating on wort

Hey,

Thought this deserved its own thread. Any idea what this stuff is? This is full boil kettle pre boil, after resting overnight with collected runnings. Below is mash detail.

36 pounds of malt with single decoction and a recirculation/direct fire mash. Did my infusion to 104, rested 20 min. pulled a decoction that took a good 80 minutes to convert then boiled 30 minutes, ran out of propane, and 45 minutes later resumed boil for another 5 min. then Returned to main mash for another 40 mins with recirc and heat, probably because the main mash temp had dropped about 10 -12 degrees. I then mashed out and sparged.

I collected the wort but ran out of daylight and let sit overnight with lid on before the boil on next day. I planned to skim this off, but it was disturbed somehow, and congealed into tape-like strands of faintly white stuff almost translucent, floating on top. I was able to skim them out.

Final post boil chilled wort tasted almost like syrup, so whatever that stuff on top was, I don't think it is harmful to the beer. Maybe the beginnings of a bacterial infection as the wort sat in warm humid pot where could have been nasties in the headspace? But didn't look or smell bad. I wonder if it could've been some type of gelatin from the prolonged low temp rest of the main mash.

TD

I would take a fairly educated guess that what you have (had) there was the beginnings of a pellicle of some sort.
Exactly the type of of thing that can occur if the mash runnings sit for a length of time (like overnight) before the boil
The grains themselves have a TON of naturally occurring yeasts and other assorted nasties that are drained right along with the mash runnings.

Dos not look like it got too bad before the boil. Let it ferment out and see what you get.

Did you mash out first? Wondering if enzyme action might cause this. You do have a few bubbles there. Could have been the start of something. The only time I ever let the kettle sit overnight I have a horrible corn flavor/smell. I know some people do this all the time but I won't try it again. Hope it turns out OK...

brewkinger said:

I would take a fairly educated guess that what you have (had) there was the beginnings of a pellicle of some sort.
Exactly the type of of thing that can occur if the mash runnings sit for a length of time (like overnight) before the boil
The grains themselves have a TON of naturally occurring yeasts and other assorted nasties that are drained right along with the mash runnings.

Dos not look like it got too bad before the boil. Let it ferment out and see what you get.

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I will say that the post boil hydro sample tasted awesome. There were no funny smells to the wort either I would add, either pre boil or post boil. I guess in retrospect, since I hadn't planned to do the full boil, although wasteful of propane, might have been beneficial to bring to a boil briefly or at least heat the BK during the wort collection to pasteurize it to some degree. It will be a long time before I consider another decoction mash and the time investment is much greater than I expected. Also much more labor intensive. With the storm rolling in, and contemplating an after dusk boil in the rain, it really wasn't a feasible option to continue with the brew session.

I had thought it might have been some type of gelatin of natural material in the malt released from the extended 95-106 degree rest for about 90-100 minutes.

TD

Poobah58 said:

Did you mash out first? Wondering if enzyme action might cause this. You do have a few bubbles there. Could have been the start of something. The only time I ever let the kettle sit overnight I have a horrible corn flavor/smell. I know some people do this all the time but I won't try it again. Hope it turns out OK...

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I did do mash out. I think those bubbles were from where drops of water from condensation on the lid dripped in, but not sure. I had no foul smell, but only smelled of sweet wort. After I skimmed and started heating I took a sample for the hydrometer, and taste tested and was good, without foul aroma.

Pellicle seems more likely than mash by product I suppose. Be curious to hear from anyone else if they've noticed this before.
It is chugging away right now. Beyond a doubt my highest OG brew ever. The single decoction boosted my efficiency to about 87% compared to 79%-80% I get with single infusion or step mashes. There is also a color change that you can see plainly darker and richer colored in the post boil decoction, compared with the main mash wort. Now I will be sure next time I try this, to pre measure all water and grain and crush, etc all the night before, so I an just roll and go without delay because it took a long time to complete it all.

TD

Yea, I would definitely say the beginnings of a lacto takeover. If the wort tasted great though, looks like you caught it in time. Glad it didn't sour your beer! Next time at least give it a boil!

daksin said:

Yea, I would definitely say the beginnings of a lacto takeover. If the wort tasted great though, looks like you caught it in time. Glad it didn't sour your beer! Next time at least give it a boil!

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Yes, I hadn't thought of these things beforehand, as I had never done it before. Now I know! If I need to do in future, will def boil for 5 min before aborting.
I guess I could have done a sour beer in worst case... Doppelbock lambic anyone?

TD

did you check the temp the next day before starting the boil?

I've seem some thick gummy protein layers on the spent grain after a decoction, perhaps it was some sort of protein/break material layer that formed?

terrapinj said:

did you check the temp the next day before starting the boil?

I've seem some thick gummy protein layers on the spent grain after a decoction, perhaps it was some sort of protein/break material layer that formed?

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The temp was over 120 but I don't recall specifically.

I was sort of thinking the same. I saw some individual pieces of grain in the main mash floating while I was focusing on the decoction, that seemed surround by a small ring of something that looked similar to the sheet of gel like material I saw the next morning. Recall that the main mash has been resting at 106 ish for 20 minutes, then another 10 or so minutes while I pulled the 27qt decoction and then took a while to heat that to 160. All the while the main mash is still hanging out in the low 100's. The decoction took significantly longer to convert than I had imagined it would. In fact it never fully converted, but mostly converted, and I grew tired after an Hour and 15 minutes, figuring the main mash I could rest until converted and it was full of enzymes. I even added a ladle of thin fluid from the main mash into the decoction at 160 thinking that would help to speed the conversion.
Again, all during this time the main mash is sitting, for nearly two hours in low 100's, and dipped into the mid 90's by the time my decoction was ready to add back. I don't know if it is some sort of glyco peptide or amino-glycan molecule material liberated from the grain during this rest? I've forgotten a lot of biochemistry over the years so wondering if there are some sharp penciled folks who know whats going on in the mash in the 94-106 temp range.

Anyway,
I'm not really sure what it was, but if it truly was a pellicle, I find it odd that there was no foul odor or taste.

TD

Reading your thread title, I was going to suggest some type of protein film. But your pictures look more like the start of an infection.

Since you boiled the wort, what ever it was is long gone. And it seems it didn't have enough time to cause off flavors.

Go for a quick boil next time if you can't finish the brew day. Or chilling via an immersion chiller and sticking in a fermentation chamber set to typical lagering temps should also be just fine.

Poobah58 said:

Did you mash out first? Wondering if enzyme action might cause this. You do have a few bubbles there. Could have been the start of something. The only time I ever let the kettle sit overnight I have a horrible corn flavor/smell. I know some people do this all the time but I won't try it again. Hope it turns out OK...

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I know this is an old thread, but it is the only post that I can find hinting at this. I did a parti-gyle beer of a Baltic Porter lager. During the parti-gyle second runnings I hit a snag, and had to collect all of the wort and I put it back into my HLT for the night as I needed to go to a dinner with the girl. I got up first thing in the morning, and started the boil process on it. After 9 hours in the HLT it had a strong corn smell and flavor with a slightly slick oily surface. I boiled it down for 3 hours trying to get rid of it, but no dice in getting rid of it completely. Did you just dump your batch like this? I over hopped it with the anticipation of potentially masking the flavor, as I have never seen something like this. It is giving me hope that the flavor is slowly subsiding as it ferments, but I don't know if it will fully disappear. Did your's ferment out, or did you just dump it? In the end, I may cook with it.

This beer is doing fine.
I am not sure what it was, but no souring effect at all.
There was some initial DMS/corn like aroma, but its gone now.
Beer is currently lagering, and has a while to go. OG 1.101 FG 1.024 Took a dang long time in the fermenter to get there too...
The last tasting from hydrometer was heavenly. I think I'm going to end up with a little under 10 gallons of finished beer. Thinking about force carbing it prior to bottling. I hate when dopplebocks are undercarbonated. Force carb will give me more control.
I will point out that I also saw some gel like stuff in the top of the primary mash tun while I was doing the decoction that took forever. it wasnt congealed into a sheet like the pic, and seemed to be centered are some floating grain husks. I'm wondering if my mash temp was at a glucan rest temp and liberated some gummy like compounds from the mash...

I did end up skimming the gel off the top mostly.

TD

I know this thread is old but I had a very similar looking wort last night. I was doing a "protein rest" for the first time and my temps were a little haphazard (BIAB) method. Basically I ended up with that gelatin looking stuff swirling around in the boil in probably 1 to 2 inch long strips. It was pretty tough stuff as a vigorous 100 minute boil could not break it all down.

Anyways, curious on how your dopplebock turned out?

Cheers

Dopplebock is fantastic! I should enter it into a competition or something! Could be a little more bitter. Definitely NOT sour or funky in any way.

TD


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