Reiterated Mash Imperial Stout

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Zephyr259

Landlord.
Joined
Jul 3, 2016
Messages
1,979
Reaction score
582
Location
Aberdeenshire
Finally got back brewing after my partigyle in October, another non-standard one with a reiterated mash.

5.3 kg pale malt
400g roasted rye
400g chocolate malt
300g medium crystal
300g Simpsons DRC
500g "Black Invert"

Split this in half, first mash at 67c for a hour then sparged up to pre-boil volume, mashed the second half at 67c for about 2.5 hrs then mashed out and sparged enough to hit 22L pre-boil. Mash/Lauter efficiency was good at 78% and I had 22L of 1.073 which was 4 points above my estimate. As such I cut the invert from 800g to 500g to hit the 1.101 target, and actually hit 1.103 sg.

Invert was as per the Unholy Mess site recipe, 11% blackstrap molasses, 89% golden syrup, although I used 55g molasses, 105g golden syrup and a very crystalised 340g jar of tesco honey. In theory this is 350 EBC but who knows, mixed up totally black but with the grist giving 81 ebc, the fact that the sugar should have made it 95 ebc is mostly irrelevant. The sugar was so I didn't have to aim as high in gravity and it should keep the FG below 1.030.

90 min boil with 35g Admiral at 60 min and another 35g at 15 min for 67 IBU.

Chilled to 16c easily due to really cold water at the moment and no issues with the GF filter clogging, transfer looked a bit slow but was steady throughout. Put it in the fridge at 15c for a few hours then pitched Wyeast 1728 Scottish Ale. I grew up 350 billion cells back in November when I originally planned to brew, that was 1 million cells/ml/P, estimated down to 180 billion cells now so I should have done a 1L starter but gave it a few hours on a stirplate in 500ml so the yeast would wake up and not overflow the 2L flask (which they almost did anyway). So I've only pitched 0.5 million/ml/P but they were active and the beer was fermenting away in about 24 hrs which is reasonable given it's at 15c, hopefully the yeast aren't too stressed and do a good job on all that sugar, I don't have a good track record once I go above 6%. If the sugars ferment 100% then this should end up about 1.026 (1.029 is the all grain prediction) for 10.1% and my biggest beer since I started brewing, think my previous was about my 2nd all grain which was around 10% but that beer went down to 1.010 so started in the mid 1.080s and was kinda rubbish, did a 9% saison but again that was a 1.070 wort which went down really low.

Time for crossed fingers and a few weeks of waiting.
 
A few weeks ago I brewed an imperial stout recipe similar to brewdogs paradox recipe, same split 12kg of grain in half for a re-iterated mash. I’ve done this a few times now but this time added 500g of Belgian candy sugar at 30 mins to the boil (raised my og from usual 1.09 to 1.1). Ended with 25L wort in my fv, transferred to a secondary and added 500ml of single malt which has been in oak for a few months. Leaving for 20 days then I’m going to bottle 😋
 
It’s Innes & Gunn and Brewdog started me brewing, similar brewdogs (Paradox Islay) a 330ml bottle is around £10 ashock1
 
Yeah, big beers are expensive, with 6kg of grain and 70g of hops I think my 15L batch would come in around £12 not including the yeast which has already brewed me several beers.
 
Yeah, big beers are expensive, with 6kg of grain and 70g of hops I think my 15L batch would come in around £12 not including the yeast which has already brewed me several beers.
Just a quick guess but think Mines under a £1 a bottle compared to Brewdogs islay Paradox £10, really enjoyed last time, so will be interesting to see what if any difference the sugar made, It finished 1.027, so sweeter ?compared to 1.021 last time !
 
Well I might have got away with this one, day 14 and it's at 1.028 sg so only 2 points off the prediction and those may well come with a bit more time. Going to leave it a few days then test again.

I left it at 15c for 5 days the starting day 6 it was increased 1c per day to 20c and held there.
 
Another test and down another point to 1.027 so going to leave it another couple of days, don't want to risk it not being finished after my recent bitter volcanoes.

Any thoughts on what I should do for bottle conditioning? I was thinking about 2 vols of CO2 which is where I like my stouts normally. Should I add a bit of fresh yeast in case this lot is a bit tired now that it's at 10.1%?
 
Another test and down another point to 1.027 so going to leave it another couple of days, don't want to risk it not being finished after my recent bitter volcanoes.

Any thoughts on what I should do for bottle conditioning? I was thinking about 2 vols of CO2 which is where I like my stouts normally. Should I add a bit of fresh yeast in case this lot is a bit tired now that it's at 10.1%?
I normally use online calculator C02 around 2.2
 
I normally use online calculator C02 around 2.2
Sorry, I now realise I wasn't very clear there, I always use the Brewer's Friend priming calculator; I was more wondering if I should pitch some fresh yeast. At least my new stir plate isn't wired through the fridge so I could set it up to grow up some fresh yeast for priming and brewing my next beer (the stirplate and flask don't fit when there's a FV in the fridge).

Alternatively, I think I have a 2nd sachet of CML sparkling wine yeast which I used to help carbonate my sours, that should be safe enough to use.
 
Sorry, I now realise I wasn't very clear there, I always use the Brewer's Friend priming calculator; I was more wondering if I should pitch some fresh yeast. At least my new stir plate isn't wired through the fridge so I could set it up to grow up some fresh yeast for priming and brewing my next beer (the stirplate and flask don't fit when there's a FV in the fridge).

Alternatively, I think I have a 2nd sachet of CML sparkling wine yeast which I used to help carbonate my sours, that should be safe enough to use.
I’ve never needed to add any extra yeast, there’s a few online calculators to use. I’ll probably bottle my own stout next week 😋
 
I’ve never needed to add any extra yeast, there’s a few online calculators to use. I’ll probably bottle my own stout next week 😋
Good to know, this yeast is good for 12% so it should have some legs left in it and the fermentation seems to have gone like clockwork. Wonder how long it's gonna take to condition...
 
Good to know, this yeast is good for 12% so it should have some legs left in it and the fermentation seems to have gone like clockwork. Wonder how long it's gonna take to condition...
What was your total grain bill. How many litres did you get and what was your OG
 
What was your total grain bill. How many litres did you get and what was your OG
6.7kg grain, + 500g "invert syrup" blend.
15 L at 1.103 OG in the fermenter, there was 2L dead volume in the grain father afterwards so I technically made 17L of wort.
 
I split the 12kg of grain to make a reiterated mash, and I use Lavazza coffee for the coffee stand at flame out. I’ve noticed only 5 days adds enough of an oaky flavour with the chunks I use (purchased from malt Miller, I’ve used a couple of times but they’ve been in Bunnahabhain malt this time for a few months), but I work offshore so they are in there for 14 days this time.
 

Attachments

  • 4E399CF8-0D7F-4985-8DD6-84E5E326AA0C.png
    4E399CF8-0D7F-4985-8DD6-84E5E326AA0C.png
    34.3 KB · Views: 98
  • 7C6D3774-6197-4AAC-B9E5-9D53DDBEBD6F.png
    7C6D3774-6197-4AAC-B9E5-9D53DDBEBD6F.png
    25 KB · Views: 84
After my first mash I sparged back upto around 22L for the second mash. Second sparge upto around 29L for the boil, I got around 23.5L into my fermenter.
it’s not a cheap brew but has tasted excellent last couple of times, I should have around 60+ 330ml bottles.
A copy of Brewdogs Paradox recipe, around £10 per bottle
 
OG 1.11 - fg 1.027 , but then I’ve added 500ml of the whisky which is around 46%abv, so it should be around 11% maybe a little higher ashock1
 
Oh yes !
The fermentation is really explosive 👹
So it’s worthwhile using a large fermenter with good headroom, the speidel 30L I use has a large hole in the top for the blow-off !!
 

Latest posts

Back
Top