AG#28 - Imperial Stout (Exceeding the Mechanical Limit!)

[bellebouche]

Glad it all came right in the end.
I'm looking at your blog for updated pics... and are you tipping the dehydrated yeast directly on top of the aerated wort? The Danstar info sheet on Nottingham is fairly explicit about a rehydration procedure before pitching a wet slurry.

I'd be concerned about the high gravity liquid it's being added to... my experience with Nottingham is very limited but I'd be keen to see how the fermentation goes and how this ultimately attenuates out.

[WishboneBrewery]

Its already started fermenting... a dry Sprinkle works just as good

[TheMumbler]

looks like a sticky day ... how much DSM did you add?

[coatesg]

I'm not following the maths here I'm afraid.. something's not right! All the malts should self convert and there'll be a load of diastatic goodness in that pale to do maize/oats etc.

Nope - you have to convert all the the amber, choc, brown, R barley, maize, oats and unmalted wheat which all won't self-convert (remember the roasted malts have zero diastatic power too; caramalt is already converted) - and you're relying solely on the pale malt (and wheat too I think) to do it for you since Munich can only self convert.

I would go for at least 60% pale malt for this type of thing - especially since the flavours from brown, choc, amber, roast barley go a long, long way.

[WishboneBrewery]

looks like a sticky day ... how much DSM did you add?

Just over 2kg.
I'll probably get another attempt on this weekend I will not be beaten!

- you have to convert all the the amber, choc, brown, R barley, maize, oats and unmalted wheat which all won't self-convert (remember the roasted malts have zero diastatic power too; caramalt is already converted) - and you're relying solely on the pale malt (and wheat too I think) to do it for you since Munich can only self convert.

I would go for at least 60% pale malt for this type of thing - especially since the flavours from brown, choc, amber, roast barley go a long, long way.

Is that strictly fully-true? Choc, Roasted are both Steepable grains so would only work as a diluter to the pale malt rather than actually having to be converted?

I'm fair tempted to keep the Pale up at 70% with 4-5% sugar added to the boil, I'm still banging my head against the recipe wall at the moment as I don't want to just copy a recipe from a book (though I am using 2 books as a rough guide, one being the Durden Park book, which is tempting in its self)

[coatesg]

Is that strictly fully-true? Choc, Roasted are both Steepable grains so would only work as a diluter to the pale malt rather than actually having to be converted?

Sorry - yup you're right there with those two - but the amber and brown do need mashing along with all the adjuncts. But it will dilute slightly as you say (as would the munich - it doesn't need more base malt to convert, but there's a lot replacing the pale there, and it doesn't really add extra enzyme for mashing other grains) - going on percentage terms probably isn't straightforward here.

The Durden Park recipes are mostly fairly simple - a fair few are only 3 or four malts and one hop. Just lots of them all!

[leedsbrew]

Here's the recipe for my RIS (akin to a Brooklyn Black Chocolate Stout but not exact!) if it helps

Fermentables
Ingredient Amount % MCU When
UK Pale Ale Malt 5.283 kg 83.4 % 8.0 In Mash/Steeped
UK Wheat Malt 0.374 kg 5.9 % 0.4 In Mash/Steeped
UK Chocolate Malt 0.354 kg 5.6 % 80.5 In Mash/Steeped
UK Roasted Barley 0.166 kg 2.6 % 53.9 In Mash/Steeped
UK Flaked Wheat 0.085 kg 1.3 % 0.1 In Mash/Steeped
UK Black Malt 0.071 kg 1.1 % 19.3 In Mash/Steeped


Hops
Variety Alpha Amount IBU Form When
UK Golding 6.8 % 46 g 36.3 Loose Whole Hops 90 Min From End
UK Golding 6.8 % 13 g 4.7 Loose Whole Hops 15 Min From End
US Cascade 7.6 % 13 g 5.2 Loose Whole Hops 15 Min From End
US Willamette 4.5 % 11 g 1.1 Loose Whole Hops 5 Min From End
US Cascade 7.6 % 11 g 1.8 Loose Whole Hops 5 Min From End

It's only 6 months old but it's awesome!

[WishboneBrewery]

Cheers
Here's my current recipe ideas...

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Imperial Entire Stout

Fermentable	Colour	lb: oz	Grams	Ratio
Maris Otter	4.25 EBC	16 lbs. 10.4 oz	7550 grams	75%
Sugar, Household White	0 EBC	1 lbs. 1.7 oz	500 grams	5%
Wheat Malt	3.5 EBC	0 lbs. 14.1 oz	400 grams	4%
Flaked Barley	3 EBC	0 lbs. 14.1 oz	400 grams	4%
Crystal Malt	130 EBC	0 lbs. 14.1 oz	400 grams	4%
Roasted Barley	1350 EBC	0 lbs. 14.1 oz	400 grams	4%
Chocolate Malt	1050 EBC	0 lbs. 14.1 oz	400 grams	4%

Hop Variety	Type	Alpha	Time	lb: oz	grams	Ratio
Challenger	Whole	7.6 %	60 mins	0 lbs. 4.6 oz	130 grams	63.4%
East Kent Golding	Whole	5.8 %	15 mins	0 lbs. 2.6 oz	75 grams	36.6%

Final Volume:	23	Litres
Original Gravity:	1.100	
Final Gravity:	1.024	
Alcohol Content:	10.1%	ABV
Total Liquor:	37.9	Litres
Mash Liquor:	23.9	Litres
Mash Efficiency:	75	%
Bitterness:	78	EBU
Colour:	342	EBC

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Imperial Stout v1.2

Fermentable	Colour	lb: oz	Grams	Ratio
Pale Malt	5 EBC	8 lbs. 6.2 oz	3810 grams	70%
Wheat Malt	3.5 EBC	0 lbs. 15.2 oz	435 grams	8%
Sugar, Household White	0 EBC	0 lbs. 7.6 oz	215 grams	4%
Roasted Barley	1220 EBC	0 lbs. 5.7 oz	160 grams	3%
Chocolate Malt	940 EBC	0 lbs. 5.7 oz	160 grams	3%
Brown Malt	150 EBC	0 lbs. 3.8 oz	105 grams	2%
Amber Malt	100 EBC	0 lbs. 3.8 oz	105 grams	2%
Black Malt	1100 EBC	0 lbs. 3.8 oz	105 grams	2%
Flaked Barley	3 EBC	0 lbs. 3.8 oz	105 grams	2%
Flaked Oats	0 EBC	0 lbs. 3.8 oz	105 grams	2%
Caramalt	20 EBC	0 lbs. 3.8 oz	105 grams	2%

Hop Variety	Type	Alpha	Time	lb: oz	grams	Ratio
Herkules	Whole	15.8 %	60 mins	0 lbs. 0.9 oz	26 grams	50%
Admiral	Whole	12 %	60 mins	0 lbs. 0.5 oz	13 grams	25%
Target	Whole	11.4 %	60 mins	0 lbs. 0.5 oz	13 grams	25%

Final Volume:	12	Litres
Original Gravity:	1.102	
Final Gravity:	1.026	
Alcohol Content:	10.1%	ABV
Total Liquor:	21.4	Litres
Mash Liquor:	13.1	Litres
Mash Efficiency:	75	%
Bitterness:	88	EBU
Colour:	326	EBC

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Imperial Stout v1.3

Fermentable	Colour	lb: oz	Grams	Ratio
Pale Malt	5 EBC	8 lbs. 6.6 oz	3820 grams	72%
Flaked Barley	3 EBC	0 lbs. 9.3 oz	265 grams	5%
Sugar, Household White	0 EBC	0 lbs. 9.3 oz	265 grams	5%
Amber Malt	100 EBC	0 lbs. 9.3 oz	265 grams	5%
Brown Malt	150 EBC	0 lbs. 9.2 oz	260 grams	5%
Roasted Barley	1220 EBC	0 lbs. 7.5 oz	210 grams	4%
Chocolate Malt	940 EBC	0 lbs. 7.4 oz	210 grams	4%

Hop Variety	Type	Alpha	Time	lb: oz	grams	Ratio
Golding	Whole	5.7 %	60 mins	0 lbs. 2.4 oz	67 grams	50%
Fuggle	Whole	4.9 %	60 mins	0 lbs. 2.4 oz	67 grams	50%

Final Volume:	12	Litres
Original Gravity:	1.100	
Final Gravity:	1.024	
Alcohol Content:	10.1%	ABV
Total Liquor:	21.2	Litres
Mash Liquor:	12.6	Litres
Mash Efficiency:	75	%
Bitterness:	88	EBU
Colour:	341	EBC

[WishboneBrewery]

Or this one... which uses about 1 KG of sugar (I'd probably use a Brown Sugar, wonder if Muscovardo would be too dark?), in theory its only an 8%-ish mash without the sugar so easier on the Mash Tun

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My Arse Imperial Stout

Fermentable	Colour	lb: oz	Grams	Ratio
Pale Malt	5 EBC	14 lbs. 7.2 oz	6560 grams	70%
Sugar, Household White	0 EBC	2 lbs. 4.4 oz	1030 grams	11%
Flaked Barley	3 EBC	1 lbs. 0.5 oz	465 grams	5%
Chocolate Malt	940 EBC	0 lbs. 13.1 oz	370 grams	4%
Roasted Barley	1220 EBC	0 lbs. 13.1 oz	370 grams	4%
Black Malt	1100 EBC	0 lbs. 6.6 oz	185 grams	2%
Brown Malt	150 EBC	0 lbs. 6.6 oz	185 grams	2%
Amber Malt	100 EBC	0 lbs. 6.6 oz	185 grams	2%

Hop Variety	Type	Alpha	Time	lb: oz	grams	Ratio
Pacific Gem	Whole	14.6 %	60 mins	0 lbs. 2.3 oz	67 grams	50%
Saaz	Whole	3.3 %	10 mins	0 lbs. 2.3 oz	67 grams	50%

Final Volume:	23	Litres
Original Gravity:	1.096	
Final Gravity:	1.020	
Alcohol Content:	10.1%	ABV
Total Liquor:	36.6	Litres
Mash Liquor:	20.8	Litres
Mash Efficiency:	75	%
Bitterness:	70	EBU
Colour:	357	EBC

Would anyone think I needed any Crystal in the mix?

[WishboneBrewery]

Or how about this, maybe going for a simple slightly lower ABV recipe makes more sense to begin with:

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Naked Imperial Stout

Fermentable	Colour	lb: oz	Grams	Ratio
Pale Malt	5 EBC	15 lbs. 7.2 oz	7010 grams	75%
Munich Malt	20 EBC	2 lbs. 1.0 oz	930 grams	10%
Chocolate Malt	940 EBC	1 lbs. 0.5 oz	465 grams	5%
Roasted Barley	1220 EBC	1 lbs. 0.5 oz	465 grams	5%
Golden Naked Oats	15 EBC	1 lbs. 0.5 oz	465 grams	5%

Hop Variety	Type	Alpha	Time	lb: oz	grams	Ratio
Golding	Whole	5.7 %	60 mins	0 lbs. 3.2 oz	92 grams	45%
Fuggle	Whole	4.9 %	60 mins	0 lbs. 3.2 oz	92 grams	45%
Saaz	Whole	3.3 %	10 mins	0 lbs. 0.7 oz	20 grams	10%

Final Volume:	23	Litres
Original Gravity:	1.090	
Final Gravity:	1.026	
Alcohol Content:	8.4%	ABV
Total Liquor:	37.6	Litres
Mash Liquor:	23.4	Litres
Mash Efficiency:	75	%
Bitterness:	70	EBU
Colour:	349	EBC

[simple one]

You could always tinker with the FG with a bit of sugar to the fermenter. That'll lower the gravity whilst increasing the abv. And then a good long secondary..... Surely it's still save-able?

[Aleman]

Looks like you are overcomplicating things on the malt side My Imperial Stout although it uses a few malts and adjuncts stays within the limits for the percentages for those grains/adjuncts. . . . and the bulk of the grain is still pale malt.

I also use a chunk of sugar to help produce a lower final gravity . . . Next time I may well reduce the amount of flaked barley . . . Not that it is required

[WishboneBrewery]

I think I'll go with my last iteration of my recipe ideas, its the most sparse on the coloured malts and no adjuncts

[pantsmachine]

Go for something lighter and blend the original with the light one and bottle.....Get some Belgian yeast in as well. NOW you're experimenting! Hmmn, Addition of ginger and apricots towards the end of fermentation

[WishboneBrewery]

Yeah! And put a chilli in every bottle!

As I said, I shall be going for the 'Naked Imperial Stout' @ a sensible 8.4%, I'm intending to Mash on Friday night, then get up and Sparge and boil Saturday.