Floating grain bed

[Sidney Harbour-Bridge]

I just added HERMS to my 3 V system and I have noticed the grain bed is floating towards the end of the mash and while sparging. Nothing else has changed. I am getting very high extract efficiencies, over 100% in brewers friend, I thought I must have put to much grain in but it has been consistent over the last three brews. The spent grain apears to just be empty husks. The wort still runs clear enough so I don't see any problems with it.

Any ideas why this might be happening?

 

[MHB]

Your doing everything right! especially your milling, which isn't a bad reason.

Worth googling "Floating Mash" it is an old brewing technique once highly favoured among UK brewers. Some UK malts give very good husk detachment and yes they can look like whole grains just with nothing in them.
As for the +100% efficiency, I suspect that's just based on brewers friend making an assumption on the yield potential of your malt that isn't exactly right, you can in fact get yields higher than the "Congress Mash" test that is used to report potential, but you really have to work on it.

Be interesting to see the grain bill and your knockout numbers.
Mark

 

[Sidney Harbour-Bridge]

Your doing everything right! especially your milling, which isn't a bad reason.

Worth googling "Floating Mash" it is an old brewing technique once highly favoured among UK brewers. Some UK malts give very good husk detachment and yes they can look like whole grains just with nothing in them.
As for the +100% efficiency, I suspect that's just based on brewers friend making an assumption on the yield potential of your malt that isn't exactly right, you can in fact get yields higher than the "Congress Mash" test that is used to report potential, but you really have to work on it.

Be interesting to see the grain bill and your knockout numbers.
Mark

Grain bill
4.2 kg coopers pale malt
36g JW dark crystal
240g Best maltz wheat malt

Mashed in 20 L at 60 C, raised temp by HERMS to 65 C, rested 1 hour.
Raised to 77 C for mash out.
Sparged 20 L at 80 C for 1 hour.

First runnings 1.057
after 20 L 1.032

Collected 35 L in kettle at 1.037

Boiling now, will post final numbers later.

 

[MHB]

That's a good yield, very close to 100% in fact. Without looking up the exact numbers for each malt, you have almost exactly 75% of the grist weight in solution. With a decent Ale Malt yielding somewhere in the 75-77% range its pretty impressive.
How are you milling?
Mark

 

[Sidney Harbour-Bridge]

That's a good yield, very close to 100% in fact. Without looking up the exact numbers for each malt, you have almost exactly 75% of the grist weight in solution. With a decent Ale Malt yielding somewhere in the 75-77% range its pretty impressive.
How are you milling?
Mark

End of boil and chilled, I have 25 ish L in the kettle at 1.05, better than the expected 24 L at 1.047, I should be able to ferment 26 L out of that at 1.047. It's clearing now while I have my dinner, I'll get it in the fermenter tonight.

I need to add, none of my gear is calibrated, kettle volume is judged from texta lines on sight glass at 5 L intervals, found by pouring 5 kg of water at a time into the kettle, they seem to relate quite well to the graduations on my 30 L plastic fermenter though.

I mill my own grains, with a 3 roller mill set at .048" I moisten the grain with 1.5% of its weight of water and turn the handle by hand, with love, maybe that makes a difference but I have been milling this way for a few years, the only thing I changed was from infusions to HERMS, it does take a bit longer between steps and I do mash in below 60 C now I can warm it gently.

So would it be fair to say I am having more floaters because more of the starch is being converted into sugar?

 

[MHB]

The husks are floating because they have a bit of air mixed in with/trapped in them.
The way you are milling will increase the size of the husk fragments (up to nearly whole shells), Malt conditioning and a three roll mill (especially at slow hand crank speeds) are working together to give you a pretty near perfect crush (must be or your yield would be lower).

About the only thing I can think of is that now that you have a HERMS you aren't doing as much vigorous stirring of the mash, pounding away at it with a spoon was probably driving a lot of the air in the husks out so they sank, now its still there so they are floating.

Not necessarily all good, you want some of the husks down the bottom of the grain bed to help form a filter when you recirculate and run off, if you have any trouble getting the wort bright it might be worth stirring the husks in, but odds on there is a fair amount down in the grist and only some is floating. Not worth worrying about unless you aren't getting really clear wort.

Mind you I think most brewers would be very happy to be bitting your numbers so I for one wouldn't be looking to make too many changes!
Good brewing
Mark