Cut Imperial Stout ingredients in half for regular stout?

[Carolina_Matt]

I saw an interesting Imperial Oatmeal Stout kit, but I don't see myself drinking 5 gallons of 10+% beer. There are 18 pounds of grain, 1 lb of sugar and 5 oz of hops in the recipe. Can I just split all of the ingredients in half to get a ~5% Oatmeal Stout, so everything is still in the same proportion? Or should I still use 5 oz of hops, with half the grains (9 lbs) and sugar (0.5 lb)? Or should I just forget the whole idea, especially since I don't have a Stout tap anyway?

I've never built my own recipe before - I've only done kits to this point - so I'm not entirely sure how it works when you alter the recipes.

 

[chickypad]

I would not suggest just cutting an Imperial stout recipe in half. It should be easy to find an Oatmeal stout recipe in the ABV range that you want, you're better off going with that. There's lots in the recipe section here (Yooper's is a popular one) or you can pull one off of any number of sites like MoreBeer, Northernbrewer, AHA.

You don't need a stout tap, many commercial stouts are served on CO2 only, or bottled.

 

[kevin58]

Do you use recipe software? Mine has a gravity adjustment tool so you would input the imperial recipe as is then use the tool to bring it down to your desired starting gravity. You may have adjust the hops manually to get the IBU range you want.

 

[ThirstyPawsHB]

Due to efficiency differences you can't just cut in half. Typically there is less mash efficiency with big beers. Knowing your's would significantly help. Brewing software is the way to go. Also sugar is odd. Maybe 1lb of dark DME in case the mash tun can not fit all the grain/water.

 

[chickypad]

I maybe should have clarified my answer. When tweaking a recipe there's more to it then just adjusting the gravity, especially something like an imperial stout. The sugar is likely there because it's a big beer with lots of specialty malts - i.e. it's a way to bump up the gravity without leaving so many unfermentables. That would not be appropriate in a lower gravity stout where you're probably more worried about getting enough body. Also IME you have to adjust down the total roasted malt percentage in a really big stout as the grainbill is so big, otherwise you end up with way too much roast. I'd think of it kind of like a heavy, rich, full-flavored soup. If you want something lighter on the palatte you're probably not going to just dilute the soup 50:50 with water, rather you'd look for a new recipe that is more along the lines of what you want.
My 2 cents. Good luck with whatever you decide!

 

[Silver_Is_Money]

It doesn't seem at all possible to me that an adequate RIS level of OG can be achieved via a mere 18 lbs. of grain plus 1 lb. of sugar. The kit manufacturer must be presuming the absolute highest level of potentially achievable efficiency to be the expected norm, rather than a quite hard to earn and achieve exception.

 

[chickypad]

Hard to know without knowing what the intended volumes are (i.e. did they calculate for only 5 gal post boil and not include losses?). I guess it also depends on what you're considering to be RIS level. I think BJCP classification is just "Imperial Stout" now, but the old RIS specs say 1.075-1.115 and 8-12% ABV. I just kegged a 1.095 stout, got around 76-77% mash efficiency with 9.56 lb of grain for 2.75 gal post boil. Scaled up that would be 19.12 lb grain (no sugar) for 5.5 gal post boil. It's coming in around 9.6%.

 

[Carolina_Matt]

Thanks for the responses and the education! The recipe is an Imperial Oatmeal Stout at the link below. I'll pass on it, and either get a regular Stout recipe, or just buy a case of Guinness when I'm in the mood.

https://www.atlanticbrewsupply.com/...erial-Oatmeal-Stout-All-Grain-Kit_p_2312.html