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Removal of the grey muck Trog? just before the boil

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Karl Cotter

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Hi all,
Has anyone removed the grey muck on the top just before the boil.

Would it make any difference to the final outcome, or is it required to be left intact?

Thanks
Karl
 

MHB

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Lots of people do, they usually call it skimming.
It is mostly made up of fine malt flour (the grey part), very high molecular weight (HMW) proteins, glucans...
Arguments go both ways, skimmers say it smells bad and better out than in. If you ignore it it will condense and end up in the trub which you should be leaving in the bottom of the kettle.
There is an argument the HMW's are most likely to bond to large polyphenols and help drag them out of the beer. Most larger kettles (say 1000L and above) only have a manhole access at the top so skimming is pretty much impossible.
There are also lots of intermediate weight proteins that tend to float around on top for a while (their solubility is very pH dependent) some of these are head building and as the answer I got from a rebound brewing consultant when I put the same question to him replied "there is a finite amount of head building ingredients in a wort; leave them there".
That said in a well hopped all malt wort there should be plenty of head building ingredients. Probably not going to make a huge difference either way, provided you are excluding the hot break properly.
Mark
 

Karl Cotter

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Lots of people do, they usually call it skimming.
It is mostly made up of fine malt flour (the grey part), very high molecular weight (HMW) proteins, glucans...
Arguments go both ways, skimmers say it smells bad and better out than in. If you ignore it it will condense and end up in the trub which you should be leaving in the bottom of the kettle.
There is an argument the HMW's are most likely to bond to large polyphenols and help drag them out of the beer. Most larger kettles (say 1000L and above) only have a manhole access at the top so skimming is pretty much impossible.
There are also lots of intermediate weight proteins that tend to float around on top for a while (their solubility is very pH dependent) some of these are head building and as the answer I got from a rebound brewing consultant when I put the same question to him replied "there is a finite amount of head building ingredients in a wort; leave them there".
That said in a well hopped all malt wort there should be plenty of head building ingredients. Probably not going to make a huge difference either way, provided you are excluding the hot break properly.
Mark

Thanks Mark for the very comprehensive reply mate. I suppose the only way is to try. Now that you've mentioned that it shouldn't hurt the beer, I'll give it a go next brew. Your comments regarding the 1000 ltr kettles etc that make it very difficult to do a skim off, indicates to me that if it really made a difference, the designers would have made an allowance for it to be done.
Really appreciated the reply Mark, thanks again.
Karl
 

kadmium

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MHB is very knowledgeable. Me not so much, but I'm in the camp of stirring it in. I find at the very least it doesn't affect the beer, and at best it helps so that's my take on it.
 

RRising

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Arguments go both ways, skimmers say it smells bad and better out than in. If you ignore it it will condense and end up in the trub which you should be leaving in the bottom of the kettle.
I did a brew yesterday and i skimmed it out and found that after chilling/ whirlpool there was little muck left on the bottom of my robobrew, even seems to be less trub that has settled in my fermenter.
 

MHB

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I would be very warry of drawing too many conclusions from that sort of observation.
Never used a Robobrew but the amount of trub formed during a boil is well linked to the malt quantity (well amount of protein in that malt) the vigor and length of the boil. I'm far from sure that the Robobrew has enough heat to get a very vagarious boil and don't know how long you boiled for. What was your boil off? Should be in the 8-10% range as a minimum.
In an all malt wort the amount the early foam you could skim off shouldn't be making much difference to the total amount of trub if you have boiled effectively.
It should have zero impact on the amount of flock that forms in fermenter (cold break).
Some more details would be helpful if you want to look at this further.
Mark
 

scomet

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The scum that forms as you ramp up to the boil yes, anything after that gets stirred into the boil; that is all taste and body and goodness.......
 

Paleman

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Are we talking straight after the mash here?
 
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