Impy Stout Efficiency - Sparge Water

[gerald8_kop]

Afternoon guys and girls

I've been struggling to get above 8 percent on my Brewzilla since the efficiency plummets above 5kg of grain but in a couple of weeks have the chance to use an 80L mash tun. For the sake of comparison (and because I love big beers) I want to give another imperial a shot but am rather unsure about water ratios.

The beer should be 9.8% for a 23L batch, and I've set the Brewfather profile to 60% brewhouse meaning grain is increased accordingly (14kg) but this means there's no sparge step calculated. If I put the brewhouse back up to 70 then it's still only 3.8L (and 12kg grain). So what's best to maximise the outcome? I see it as these options:

1) 60% brewhouse = more sugar but thicker mash and no sparge
2) 70% brewhouse = less sugar but more lucid mash and small sparge
3) Ignore Brewfather and cap the striker water (what volume?) = much thicker mash but decent sparge
4) Oversparge but boil longer to incr boiloff (it's new kit so I don't know the rate) and use less hops to account for IBU = more guess work/scope for error
5) DME = feels like cheating/like I'm not learning as much/like it's less of a side by side comparison with the BZ

Any further thoughts or suggestion would be amazing. I don't really have my heart set on a particular method (ignoring #5) but want to place my malt miller order this week and so need to settle on a plan.

Thanks!

 

[Jim Brewster]

Not sure if this helps but I saw an imperial stout video where the brewer did a double mash, i.e. split the grain bill in two, mashed half with no sparge then mashed the second half in the wort from the first mash

 

[dad_of_jon]

I'd say get some dark dme to bump up any og shortfall. most of the character will come via the grain.

(But then i'm generally a DME brewer but use grains as required)

 

[gerald8_kop]

Not sure if this helps but I saw an imperial stout video where the brewer did a double mash, i.e. split the grain bill in two, mashed half with no sparge then mashed the second half in the wort from the first mash

That's a great video - not sure I've stumbled across his page before so I will have to follow - thanks!

I've considered doing a reiterated mash before on my BZ as it seems handy/straight forward if running out of mash tun or grain tube. But I still don't think I understand just what the water ratios should be. In the video he says split the bill in half, and then mash with the first chunk before sparging as normal and then mashing a second time.

'sparge as normal'

Not sure what sparge volume that would be. In the case of my 60 percent efficiency option that still means no sparge. In the case of 70 it would still be 3.8L of sparge.