Boosting ABV in a Porter Recipe

[LewisA]

Hello Homebrew Forum,

I'm hoping to get some guidance on adjusting a recipe to increase the ABV without changing the overall flavor profile too much. I’m currently brewing a porter that’s around 5% ABV, but I’d like to bring it up to over 8% so it qualifies as an imperial stout for an upcoming homebrew contest. I’m using the following grain bill:

• Pale Ale
• Flaked Barley
• Smoked Malt
• Roasted Barley

To achieve the higher ABV, should I primarily increase the Pale Ale and Flaked Barley, or would it be better to adjust all the malts proportionally to maintain the same level of smokiness and overall balance etc?

Thanks in advance!

 

[Larse]

Did you try putting it through a brewing calculator like Brewfather? If it was me, I'd increase everything proportionally or if that means an unmanageable volume of wort, just leave as is and reduce the wort volume by boiling longer or sparging less.

 

[foxy]

To achieve the higher ABV, should I primarily increase the Pale Ale and Flaked Barley, or would it be better to adjust all the malts proportionally to maintain the same level of smokiness and overall balance etc?

Thanks in advance!

No, the more grain going in the less the efficiency. To make a BIG beer use a reiterated mash.
https://byo.com/article/reiterated-mashing-multiple-mashes-for-massive-brews/

 

[peterpiper]

Yes proportional.
Though I went with de-husked roast barley (7%), which is meant to give less harsh astringency (tea-bag tannin flavour).

But rather than struggling with a big mash, maybe do a partial mash recipe. Replacing part of pale malt grain, with LME or DME added during boil.

For my Award Imperial Stout, 21L 17% ABV. I mashed 5.7kg of grain, then added 3kg of TMM premium light LME at boil, and 1.2kg dextrose as ferment progressed (in 200g additions at days: 2; 6; 9; 11; 12; &15).
I tweaked the recipe (pale malt grain %) in Brewfather, so I'd use a full 3kg of LME.
The stout's been maturing on oak strips, since January, for sharing this Christmas.

You should make sure there's plenty of oxygen at start of ferment, with a whisk or bubbler; include yeast nutrient; and use a starter (so yeast isn't stressed by a high initial OG).

Prepare starter two days earlier- preferably from a boiled DME base with OG 1.040-1.050. Chill starter in fridge (the night before needed); once settled pour off liquid; then allow slurry to reach 19°C before pitching. ( I did a 1 gallon starter, with Nottingham yeast).
Alternative to starter, is to use the yeast cake from a previous batch of small beer (= low-med OG).

With strong beers, allow more headroom, for a larger Krausen. For the 17% stout, it needed double the volume! And on day two, I had to split the 21L batch between twio 26l bins.