Hitting my IBU target - Believe recipe or Brew Father?

[Matheos]

Hi guys.

I have a brewday coming up on Friday and could use some input on this dilemma of mine.
So I am brewing this simple Red Ale Recipe: Ruabeoir Red Ale

• 11.25 lbs (5.1 kg) British pale malt
• 6.0 oz (170 g) Crystal (40 °L)
• 6.0 oz (170 g) Crystal (120 °L)
• 6.0 oz (170 g) Roasted Barley (300 °L)
• 1.25 oz (35 g) Kent Goldings hops, 5% AA (60 min)
• White Labs WLP004 Irish Ale, Wyeast 1084 Irish Ale, or Fermentis Safale US-05

Yield: 6 gallons (22.7 L)

Original Gravity: 1.054 (13.4 °P)

Final Gravity: 1.014 (3.6 °P)

ABV: 5.20%

IBU: 25

SRM: 17

Boil Time: 60 minutes

Efficiency: 70%

I always input all the ingredients that I will use into brew father in order to get a good idea of if I am hitting the IBU targets, sparge water and so on.
So I did that, and having input everything the same as the recipe (though, I have my own Equipment profile which obviously affects a bit), I realised that I am undershooting the given IBU target by a whole lot.
Link to my brewfather recipe: Brewfather
I cannot figure out why. I have the same AA on the hops in brew father as the ones given in the recipe. Everything else is also about the same.
Through googling I found a replica of this recipe which someone had input into brewersfriend, and here the IBUs look about correct: Irish Red Ale (Ruabeoir) | Irish Red Ale BIAB Beer Recipe | Brewer's Friend (at least way closer).
The hops I got from my homebrew shop were only 4,4AA though, so I will obviously adjust my recipe for that, but I would first like to figure out why I cannot replicate the exact recipe, even as well as the guy on brewersfriend?

Should I stick with brewfather and do a bittering addition of 55g(!) of 4,4AA hops (according to brewfather), or should I stick with the recipe + adjusting for lower AA?

 

[BrewnWKopperKat]

[ ... 18 IBUs in BrewerFather, 23 in BrewersFriend ... ] I cannot figure out why.

It is likely that BrewersFriend and BrewFather have slightly different approaches for estimating IBUs. Configuration options are also a consideration.

 

[dmtaylor]

You have been inconsistent with your batch sizes. On the first recipe posted above, it's 6 gallons. In Brewfather, it's 25L which is 6.6 gallons. Then on Brewer's Friend, it's 5.5 gallons. So you have a volume decision to make.

It doesn't help that the Brewfather calculation is not giving you an accurate IBU calculation. Personally for 6 gallons I calculate 23 IBU (assuming 5% alpha). The value of 18 is low even if corrected for volume.

Pick your volume. Then pick a calculator other than Brewfather.

 

[Matheos]

You have been inconsistent with your batch sizes. On the first recipe posted above, it's 6 gallons. In Brewfather, it's 25L which is 6.6 gallons. Then on Brewer's Friend, it's 5.5 gallons. So you have a volume decision to make.

It doesn't help that the Brewfather calculation is not giving you an accurate IBU calculation. Personally for 6 gallons I calculate 23 IBU (assuming 5% alpha). The value of 18 is low even if corrected for volume.

Pick your volume. Then pick a calculator other than Brewfather.

Google tells me 5.5 gallons is 25L. I now realise this is obviously wrong... Maybe it uses some "Other gallon"... Can't get my head around the imperical system haha...

Hence why I assumed these two were comparable.

But bottom line, ye maybe you are right. I should give another calculator a try then.

 

[dmtaylor]

Google is telling lies!? Never!!

StrangeBrew software gives different options for different gallons. Yeah, I guess Imperial Gallons is a thing, somewhere (or nowhere?!). Mine says for US Gallons:

 

[BrewnWKopperKat]

With out a label to clearly state which regional gallon is being used, a 'comma' rather than a 'period' is a hint.

On the other hand:

 

[Matheos]

@dmtaylor
@BrewnWKopperKat
Haha Honestly that is one me. I never considered that there were to kinds of gallons in existence... Very European mistake...

Strangebrew looks interesting, Would you recommend it? Could give it a shot in place of brew father

 

[BrewnWKopperKat]

No experiences with (or opinions of) Strangebrew,

 

[hout17]

Strange Brew? This is the only Strange Brew I know of lol.

 

[dmtaylor]

Not many people use StrangeBrew (which is indeed Canadian, so, go to strangebrew.ca). It is really great, I like it a lot. I've had it since 1999, and I have literally about 1000 recipes in my database, so it's difficult to part with. If I had to start all over, I'd say it's still great, but I might also consider BeerSmith, or just stay online with Brewer's Friend which might even be better in some ways.

 

[Matheos]

Thanks guys. Seems like my problem here was mostly that I am European lol. I just tried inputting my recipe into brewersfriend in metric units, exactly as I had it in brewfather and indeed they do match up. Seems like they do calculate the IBUs in the same way.

According to both, I will need 55g of EKG 4.4AA @60 to reach my desired 25Ibus with my batch size. Now I am just concerned whether the original recipe IBUs are given in Tinseth or rager... haha

Thanks for the suggestions on calculators. I will see which one best suits me.

 

[dmtaylor]

They all use Tinseth, thankfully. Tinseth is the most accurate formula. I mean it's not perfect, but it's as good as we can get without getting overly complicated (there are alternatives out there that require a zillion inputs -- not necessary for most practical intents & purposes).

 

[Matheos]

They all use Tinseth, thankfully. Tinseth is the most accurate formula. I mean it's not perfect, but it's as good as we can get without getting overly complicated (there are alternatives out there that require a zillion inputs -- not necessary for most practical intents & purposes).

Ok thanks, good to know

 

[rburrelli]

When I first started using Brewfather I made an error on what my boiling temperature was in my profile. It directly affected my ibu calculations a lot. Once i corrected by entering my altitude things adjusted.