13% imperial stout advice please

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floydmeddler
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13% imperial stout advice please

Post by floydmeddler » Sun Oct 03, 2021 12:21 pm

Hi guys,

I'm planning a huge imperial stout and am looking for any helpful advice before I brew it. I guess my main worry is that it won't finish low enough and I'll be left with a FG of 1.040!! It's happened before.

So far, I've decided to do an overnight mash starting at 64c in the hope of creating more fermentable sugars and bumping up the efficiency. Any more advice would be most welcome. Particularly on suitable yeast strain. Here's the recipe. It's Brewdogs/Amundsen's collab 'Mallow Mafia'. I won't be adding marshmallow though! Will bitter with Magnum. Cheers!


Size: 21.0 L @ 20 °C
Efficiency: 75.0%
Attenuation: 75.0%
Calories: 433.26 kcal per 12.0 fl oz

Original Gravity: 1.128 (1.000 - 1.100)
Terminal Gravity: 1.032 (1.000 - 1.100)
Color: 51.84 (0.0 - 50.0)

Ingredients:
6,002.5 g (50.3%) Maris Otter - added during mash
245.0 g (2.1%) Dark Crystal Malt - added during mash
980.0 g (8.2%) Wheat Malt - added during mash
490.0 g (4.1%) Roasted Barley - added during mash
612.5 g (5.1%) Brown Malt - added during mash
245.0 g (2.1%) Oat Flakes - added during mash
1,715.0 g (14.4%) Chocolate Malt - added during mash
980.0 g (8.2%) Munich Malt - added during mash
656.25 g (5.5%) Light Brown Sugar - added during boil, boiled 5 m

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Re: 13% imperial stout advice please

Post by IPA » Sun Oct 03, 2021 12:38 pm

A suitable yeast would be a J1 slant from Brewlab. It came from a bottle of Courage Russian Stout brewed in1984. I revived it about five years ago and sent it to Brewlab for storage.
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Re: 13% imperial stout advice please

Post by floydmeddler » Sun Oct 03, 2021 1:09 pm

Cool! Cheers IPA

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MashBag
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Re: 13% imperial stout advice please

Post by MashBag » Mon Oct 04, 2021 1:48 pm

I would add the light brown sugar much later in the ferment. Draw off some of the wort (about a litre or two) dissolve the sugar in it and return.

Use a strong starter, or good yeast dose.

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Re: 13% imperial stout advice please

Post by f00b4r » Mon Oct 04, 2021 2:48 pm

Lots of healthy yeast! We are talking 5 packs of dry yeast or a really big starter; in the case of wet yeast you are probably better brewing as weaker beer and then using the yeast cake.
Also check that the yeast that you are using will tolerate the ABV that you want to reach, a lot will not.

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Re: 13% imperial stout advice please

Post by guypettigrew » Mon Oct 04, 2021 3:14 pm

MashBag wrote:
Mon Oct 04, 2021 1:48 pm
I would add the light brown sugar much later in the ferment. Draw off some of the wort (about a litre or two) dissolve the sugar in it and return.
Good call, MB. For two reasons.

Firstly, sugar added during the boil will be subject to the usual efficiency losses caused by the hops in the boiler retaining some of the wort. So 660g of sugar in the boil won't equate to 660g in the fermenter.

Secondly, with a beer of this high OG the yeast may struggle. Best to let it get going, chomp through some of the sugar and drop the gravity, then add the sugar.

Guy

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Re: 13% imperial stout advice please

Post by MashBag » Mon Oct 04, 2021 5:50 pm

guypettigrew wrote:
Mon Oct 04, 2021 3:14 pm


Secondly, with a beer of this high OG the yeast may struggle. Best to let it get going, chomp through some of the sugar and drop the gravity, then add the sugar.

Guy
I think we are agreeing here. Are you saying...

... chomp through some of the sugars (in the wort) and drop the gravity, then add the sugar (light brown)?

Yeast do like a bit of late sugar, particularly if added when they are just slowing down.

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Re: 13% imperial stout advice please

Post by MashBag » Mon Oct 04, 2021 5:53 pm

While we are on the subject... Why do recipes suggest adding sugar to the boil. Always seems pointless to me. Must be missing something.

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floydmeddler
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Re: 13% imperial stout advice please

Post by floydmeddler » Mon Oct 04, 2021 6:50 pm

Cheers guys. Sugar at end of ferment makes sense. It's how I add honey actually.

F00bfr, the yeast cake idea actually crossed my mind. I could brew a classic 4% English pale and use the yeast. It'll be a seriously messy ferment I imagine! Blow off tube will be required for sure.

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Re: 13% imperial stout advice please

Post by Jocky » Mon Oct 04, 2021 9:51 pm

From a starting gravity of 1.130 I wouldn’t be worried about a FG of 1.040. I certainly don’t think you need an overnight mash. 90 minutes at plus a slow sparge should be fine.

For a beer this big you’re going to need a lot of yeast though. Ideally a yeast cake from a recently finished beer, using a yeast that has a decent alcohol tolerance.
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Re: 13% imperial stout advice please

Post by Northern Brewer » Tue Oct 05, 2021 3:43 pm

floydmeddler wrote:
Sun Oct 03, 2021 12:21 pm
Particularly on suitable yeast strain.
WLP540 Abbey IV is a useful yeast for this kind of thing, it's British despite the name and has good alcohol tolerance.

This presentation has some useful tips :
https://quaff.org/wp-content/uploads/20 ... tion-1.ppt

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Re: 13% imperial stout advice please

Post by floydmeddler » Sat Oct 09, 2021 9:00 am

Thanks guys. :-)

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