Calculating Lactose Percentage of grain bill

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Rob2010SS

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So, first time using lactose. I'm going to be making a milk stout. I know how to calculate pounds of grain from percentages. My problem is that I'm having a hard time going the other way.

I know I want to use 1lb lactose. How do I figure out the correct percentage of the recipe that lactose accounts for and how do I calculate what it's contributing to the gravity?

I thought you could just work backwards but the math didn't seem to be working out...
 
1 lb of lactose will add 8 points of gravity in 5 gallons of beer (e.g. goes from 1.010 to 1.018).

I would not calculate as a percentage of grain bill since it’s not being mashed.
 
I'm fairly certain that lactose is mostly un-fermentable. Most of time I've seen it calculated more as a oz/gal instead of a percentage of your grain. If you have beersmith or something similar you can plug it in and it should add it to your gravity but I think its something like 1.042pppg?
 
Ok, my only other question is why other people do it then...

Usually because that's just the way their software does it. In the example you give, it's particularly confusing as the total grain bill is given as 11.38lb excluding the lactose, but the percentages are based off 12.38lb including the lactose. Don't sweat it.

As an aside, it's worth comparing with the original milk stout - Mackeson's, from before Whitbread had messed it up too much. No crystal at all, and 11.5% of fermentable sugar in addition to the lactose.
 
Alright, final question...

I built my milk stout recipe and with the lactose, came out a bit heavier than I was planning on.

My plan was...
1.065 OG

What resulted from my recipe is...
1.069 OG
1.023 FG
6.12% ABV
50 SRM

1. Is 6.12% too high for a milk stout? I know the BJCP guidelines cap it at 6%
2. Is 50 SRM too dark? Again, BJCP caps it at 40 SRM.

Thanks everyone
 
There's no way anyone will notice a 0.12% abv difference, the calculator you are using is making lots of assumptions and estimates to reach that value, don't sweat it. 40 is jet black, 50 will be to. I'd be worried about it being too roasty but I don't love roasty beers, just like I'm sure there's people who worry about beers being being too hoppy when there's actually no such thing.
 
1. Is 6.12% too high for a milk stout? I know the BJCP guidelines cap it at 6%
2. Is 50 SRM too dark? Again, BJCP caps it at 40 SRM.

The difference between 6.12 and 6, or 40 and 50 SRM is negligible. The BJCP are exactly that, just guidelines. If you aren't entering a competition it doesn't really matter, I wouldn't sweat it.
 
+1 to don't sweat it unless you're entering a competition.

However, this is one of the BJCP categories that I have a bit of a problem with, even in 2015 form. This is one of the few styles that one can trace back to a single brewery, but modern (UK) Mackeson wouldn't qualify under the BJCP definition which is just mad. It hasn't been over 4% since WWII, the current cans are only 2.8% (thanks to a tax band at that level). As an aside, it's an example of ABI not knowing what to do with some of the hugely important British brands they've inherited, if they cared more about beer than focus groups they would release a Mackeson "Original" back up at 4.5% or so. It would sit very nicely even as just a seasonal amongst their craft stuff.

But certainly to British tastebuds, milk stout is a low ABV style, even 5% would be high.
 
Thanks for the information! Appreciate it. I'll probably post the full recipe in a new thread for critiquing. My goal is less roasty, more chocolatey.
 
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