My first Imperial Stout

Discussion in 'Beer Brewdays!' started by foxbat, Jun 24, 2018.

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  1. Jun 24, 2018 #1

    foxbat

    foxbat

    foxbat

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    Got up early doors this morning to get a 12 litre BIAB batch of Imperial Stout on the go. Hoping to be done and dusted before the England game at 1pm. The idea's to get this one bottled and aged for Christmas. This was my first big dark beer so I'm totally out of my comfort zone (a good thing) and had to do a fair bit of planning to get things where they needed to be.

    Here's the abbreviated recipe for a guesstimate of 70% efficiency, that's 10% reduced from what I normally get since everyone says to lower your expectations for these types of beers.

    Est. OG: 1.090
    Est. IBU: 84

    64% Pale malt
    20% Munich malt
    7% Roast barley
    4% Crystal 240 EBC
    3% Low colour chocolate malt
    2% Special B 380 EBC

    11g Polaris 18% AA 60 mins
    11g Polaris 18% AA 30 mins
    11g Polaris 18% AA 15 mins

    Crushed the grains with the grinder set to 32 mils:

    [​IMG]

    Mashed at 66C for 90 minutes giving it a quick stir at 45 mins because it was quite thick. Dunk sparged the bag for 10 minutes with 6 litres.

    Pre-boil gravity was 1.070 for an 82% mash efficiency, easily beating the estimate of 1.065. Well pleased with my mash efficiency on this one.

    Got the boil on nice and quick with this smaller batch.

    [​IMG]

    Boiled for 90 minutes. Normally I do 60 minutes but in order to get enough water available for the sparge I had to boil for longer.

    Oddly enough I got a lower boil-off rate of 2.8 litres/hour instead of my rate of 3.5 litres/hour despite the boil looking just as vigorous as usual. This meant the wort wasn't reduced as far as expected and I ended up with an OG of 1.088 - saved by my better than expected mash efficiency. Is lower boil-off expected for big beers? I don't know. Anyway 1.088 is fine by me and should result in a 9.0% beer.

    [​IMG]

    Transferred 13 litres to the fermenter and pitched a 1.5 litre decanted starter of Wyeast 1728 at 18C. No action yet from the blow-off tube but I'm not concerned. It'll probably have kicked off by the morning.

    [​IMG]

    Overall BH efficiency was 77%, only 5% down from the usual. Now if I can just figure out why I got a lower boil-off I'd be sorted for the next time.

    Looking forward to trying this one at Christmas if I can keep my hands off it for that long.
     
    Zephyr259, Dutto and Ajhutch like this.
  2. Jun 24, 2018 #2

    Ajhutch

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    Nice one! I did my second RIS last weekend and came in 8% below my normal, 5% is very nice. The biggest factor (I find, don’t come at me scientists!) for boil off is ambient temperature, in this heat you’ll get less boil off than in winter. I’d be very keen to do a swap of these as and when if you’re up for it.
     
  3. Jun 25, 2018 #3

    foxbat

    foxbat

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    I checked this morning and its bubbling away at about 2 bubbles per second so it looks like the yeast are having a bit of a feast.

    I'm planning to hold it at 18 until the bubbling dies down then leave it at 21 or so for a few weeks to finish.

    Yes OK I'd be up for a swap when these have come good.
     
  4. Jun 25, 2018 #4

    dad_of_jon

    dad_of_jon

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    I'd suggest trying one a month to see how it develops. I like imperials when younger and sweeter (3-6 months) and once they turn into liquorice bombs I age them. By then they're usually 12 months+ old. I have 6 king kong's put away and they will be 2 years old this xmas :eek:
     
  5. Jun 27, 2018 #5

    foxbat

    foxbat

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    60 hours and fermentation has slowed from rapid fire down to a burst in the blown off tube every 4 or 5 seconds. Turned the temperature from 18 up to 20 to compensate.
     
  6. Jun 28, 2018 #6

    cheshirehomebrew

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    Looks great, I might try a stout so its ready for Christmas, I wont have enough bottles spare to do the usual 25 litre batch so I might just do a couple of gallons instead
     
  7. Jun 28, 2018 #7

    foxbat

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    At this strength a half-batch isn't a bad thing. It also keeps the grain bill down to a reasonable size.
     
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  8. Jun 28, 2018 #8

    foxbat

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    I couldn't resist drawing off a sample today. It's down from 1.088 to 1.020 in 4 days flat. 9.1% and 76% attenuation so far. I knew I could trust the Scottish yeast to be up for a fight. I guess there'll be a couple more points in it before it's done cleaning up.
     
  9. Jun 28, 2018 #9

    Sadfield

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    Best clean yeast ever, WY1728/WLP028.

    Sent from my E5823 using Tapatalk
     
  10. Jun 29, 2018 #10

    foxbat

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    I'm not convinced those two are one and the same. My experience with WLP028 is that it's less flocculent and takes longer but does give a lovely clean malty finish. Eventually. The manufacturer's specs are quite different too.
     
  11. Jun 29, 2018 #11

    Sadfield

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    Perhaps. Can't say I've had a problem with flocculation on either and get similar results, in that neither mutes hops and give a nice residual malt sweetness. Consensus opinion is they are both mcewans strains.

    Sent from my E5823 using Tapatalk
     
  12. Jun 29, 2018 #12

    cellarbrew

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    Hi foxbat,

    The beer looks and sounds great. I am intrigued by the equipment you used. Looks like some sort of electric boiler? Can you share details of your boiler as I am looking to go electric myself. Thanks!
     
  13. Jun 30, 2018 #13

    foxbat

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    The boiler is a converted 38.5l thermopot from angel homebrew. They do the conversion, you just tell them what you want in terms of valve and element and they do it. I posted some photos here. It's all you need (except the chiller) to do no-sparge BIAB. I do a dunk sparge so I also have a separate stockpot for that. I control the heat during the boil using an external box that I put together myself, documented here.

    The 33l stainless fermenter is a relatively new addition. It's this one from Brewbuilder. The fittings are the same tri-clamp style used by major breweries and dairies because there are no threads or other gaps to harbour infections. With a butterfly valve and blanking plate on the bottom and a tri-clamp barb on the top lid for a blow-off tube it just fits inside my Curry's brewfridge.
     
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  14. Jun 30, 2018 #14

    cellarbrew

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    Awesome. Thanks a lot for all the links and info. I have been busy reading and cogitating today. Hopefully get something built and brewing up a stage from my current small 12l stockpot that I boil on the stove.

    Bit unsure about BIAB. I always find the grain husks get stuck in the bag and its a right pain to clean
     
  15. Jun 30, 2018 #15

    foxbat

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    The answer to that is easy. Don't. Rinse the large chunks out then let the bag dry. Once its dry shake out the husks. Easy when it's dry.
     
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  16. Jul 12, 2018 #16

    foxbat

    foxbat

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    There's been no activity in the blow-off tube for a few days so I decided to bottle it. FG is stable at 1.020 so basically it fermented fully out in the first 4 days and has just been cleaning up for the remaining 14 days. Great yeast that 1728.

    Batch primed for 2.0 vols and got 22 bottles (11 litres). I took the precaution of re-yeasting with a pinch of dried Nottingham in each bottle just in case the 1728 is a bit knackered after all the work it's been doing. The sample jar tasted great; very smooth, roasty and warm already. ABV will be 9.1%. Now all I need to do is try to forget about it until Christmas. Not going to be easy.
     

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