Help with All Grain Recipe

[ClownPrince]

In 20 litres that would take you to an original gravity of 1.052 and a colour of about 6ERM/12EBC which equates to pale malt with 2% crystal 60L - say 5kg Otter and 100g crystal 60L.



You're not an idiot, you just lack knowledge. And that is fixable, unlike being an idiot.

As others have said, software is a big help when building your own AG recipes - whether it's the paid ones, a free one like Brewtarget, or a website like Brewersfriend. But if you're not ready for that, the numbers happen to fall out for a good rule of thumb :

1kg base malt in 20 litres at 70% efficiency -> ~10 gravity points which with a medium-attenuation yeast -> 1% ABV.

So :

5kg base malt in 20 litres at 70% efficiency -> 1.050 original gravity which with eg S-04 yeast -> 5% ABV

In fact with modern malts you tend to get a bit more than that, but it's close enough (or just assume slightly efficiency of say 68% to make the numbers work). Base malts are any malts with a "full" amount of enzymes for breaking starch down into sugar - pale malt, pilsner, even slightly darker ones like Vienna. But the enzymes get killed by the longer cooking needed to make darker malts, and the starch itself becomes less accessible, so assume speciality malts release half as much sugar per kg compared to base malts. So :

Instead of 5kg base -> 1.050, you want 4.9kg base + 0.2kg (4%) crystal -> 1.050 and so on. But 2-4% crystal is a pretty flexible base for most styles.

Brewhouse efficiency is a measure of how much sugar you get out of the grain versus the theoretical maximum. Somewhere around 70-75% is considered typical for BIAB, all-in-one systems like Grainfather get over 80%. I wouldn't sweat efficiency too much - what matters is being able to predict efficiency rather than its absolute number (unless you're brewing for profit), so consistency is more important. If your efficiency is low, all it means is you have to add an extra 50p of malt, which is nothing in the global scheme of things. So 70% efficiency is a reasonable assumption, but your first one or two AG brews will probably end up closer to 60% so it's worth adding an extra 15% or so grain in those early brews - better to go a bit higher than end up with gnat's urine! For the same reason it's no bad idea to have some DME to hand if it needs a bit of a boost.

Attenuation is a measure of how well a yeast converts a sugar solution into alcohol. Typically you end up with final gravity (FG) at about a quarter of the original gravity (OG), implying an attenuation of 75% - formally, apparent attenuation = 1 - (FG/OG) or = (OG – FG)/OG.

So a 75% yeast will take 1.050 wort to 1.0125 (just divide 50 by 4) and ends up at about 5%. So at 75% attenutation it's roughly 10 points of gravity ->1% ABV, and it changes by about 0.2% ABV for every 3% attenuation up or down. So you might get 68% attenuation from a yeast like Windsor, which would end up below 4.6% but with more body, or 85% with a saison yeast for 5.6% and a drier, thinner beer.

All the above are not completely accurate, but they are close enough to have in your head to be useful reality checks - or when you just need to do a quick brew without getting the computer/phone out.

Thank you. That's brilliant. I might have to print that response off and tape it to my FV's until it sinks in.

 

[An Ankoù]

5kg of Marris Otter and .5kg of crystal 40. I've gone higher on the MO in the past but this is my current incarnation of the recipe. Hop it however you like but I use 100% centennial.

@ClownPrince you asked to treat you as if you know little. Don't know where you're based but we don't commonly use degrees Lovibond in the UK. The crystal malt 40 would be a light crystal malt here of about 105 ebc. You could go as much as 150 ebc and use a little less.

 

[ClownPrince]

@ClownPrince you asked to treat you as if you know little. Don't know where you're based but we don't commonly use degrees Lovibond in the UK. The crystal malt 40 would be a light crystal malt here of about 105 ebc. You could go as much as 150 ebc and use a little less.

Learning more all the time. So Crystal 60 to some folk isn't Crystal 60 to everyone?

 

[An Ankoù]

Learning more all the time. So Crystal 60 to some folk isn't Crystal 60 to everyone?

Correct. 60 degrees Lovibond is about 158 ebc, which is a medium crystal.
BUT be careful: different maltsters describe their crystal malts differently regardless of the colour measurement. So, if you buy from Geterbrewed, they stock Crisp's, whose medium crystal is what everyone else would call a dark crystal and so for 150ish ebc you would need to order their light crystal (which everyone else calls medium). Always go by the colour value rather than the description. Most UK literature and recipes measure in ebc while most American (and Ron Patterson) use degrees Lovibond. Some give both.
Another complication: American recipes use American gallons (and pounds and ounces); an American gallon contains about 20% less than an "Imperial" gallon. Best to convert to litres and go from there.