My first own recipe all grain!

[blandy]

Hi everyone.

Over the past couple of days I have been plotting and schemeing with one of my brewing mates as to what we should be brewing. Finally we came up with the idea to do a Bitter and an IPA, as we figured they would use the same sort of yeast, so we could therefore get away with only one wYeast sachet.

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Anyway, yesterday we put down the bitter:

2.6kg pale malt
125g roasted barley
700g amber malt

45 minute boil (boil volume 10L)
Cascade hops: 40g for 45 mins, 20g for 15 mins, 10g + irish moss for 5 mins. (Target IBU about 50)

wYeast "Flying Dog Ale Yeast" (one of G&G's "very special yeasts")
nicknamed "Fido"

final volume 19L

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So we mashed, we drank Bamburg Rauchbier, we sparged and boiled, we drank coffee, we chilled, we drank pale ale.
Then we unleashed Fido...

The IPA will be mashed next Saturday, although since my mash tun can only cope with about 4kg of malt, we'll add some pale malt extract syrup to make it up to the desired powerfullness.
All we've realy thought about with this one is:
- target IBU: Somewhere in the vecinity of 60-70
- abv 9% and beyond
This will definately NOT be a session beer!

[muddy]

Top work there Blandy.

You sure as hell didnt go for a wimps beer first up!

[blandy]

Hi Muddy,

No way am I ever going to make a wimp's beer! Let's face it, If you make a 19L batch, then you're going to have to drink a lot of wimpy beer. I've got much better things to do with my liver.

I'm not entirely new to mashing, just the first time I've done my own recipes. We've gone for high IBUs because last time we compensated too much for hop pellets (vs cones) and reduced the mass by about 40% in stead of 15%. This resulted in very drinkable beer, but nothing that would ever come close to knocking your socks off.

[gregb]

Not getting a recipie quite right first go is just a good excuse to brew it all again, eh.

Cheers,
Greg

[Ross]

Anyway, yesterday we put down the bitter:

2.6kg pale malt
125g roasted barley
700g amber malt

45 minute boil (boil volume 10L)
Cascade hops: 40g for 45 mins, 20g for 15 mins, 10g + irish moss for 5 mins. (Target IBU about 50)

wYeast "Flying Dog Ale Yeast" (one of G&G's "very special yeasts")
nicknamed "Fido"

final volume 19L

Not sure how you calculated your IBU's there, but assuming cascade pellets at AA 5.5% your total IBU's will be approx 24, nowhere near your 50 target Out of interest, what was your OG in the fermenter?

Cheers Ross

[blandy]

Ross,

IBU = (weight in g)x(%utilisation)x(%alpha)/(final Volume)/(10)

for the first contribution:

m = 40, %U = 29%, % alpha = 5.9%, Volume = 19L

==> IBU from this part of the boil =

40x30x5.9/(10x19)

= 36

Second contribution:

m = 20, %U = 8%, % alpha = 5.9%, Volume = 19L

IBU = 5

the 5 min boil is negligable

total IBU = 41


OK, so I get an IBU of about 41. Good point in it being not as bitter as I thought, but 41 is still pretty big.

How did you do your calculations?

Final SG was about 1.039

Thanks for getting me to re-check my calculations.

[lethaldog]

I whacked this recipe into beersmith for you blandy and i also came up with 24 ibu and at 80% efficiency it should be about 4.2% with an og of 1.044 and an fg of 1.011, obviously thats just an estimate but its usually pretty close, hope this has helped

Also with your og of 1,039 your looking at about 72% which means you would be up to 25.8 ibu's and down to about 3.8% if it finishes in the vacinity of 1.010, sorry didnt read your post properly which is why i added

[blandy]

Also with your og of 1,039 your looking at about 72% which means you would be up to 25.8 ibu's and down to about 3.8% if it finishes in the vacinity of 1.010, sorry didnt read your post properly which is why i added

I think this is where our calculations differ. The IBU's I've calculated don't take into account the specific gravity of the total final volume.

My IBU calculatoins come from "te complete joy", about page 265. Just based on boil SG, hop mass, boil time, final volume, and alpha acid content.

I've calculated previous recipes using this method, and got the desired results. Also Charlie Parpazian's recipes in the book use the same method, and I have checked his calculations and the results match mine.

[Ross]

Blandy,

I don't believe your calculations are correct for a beer where you have added the final volume by top up. The utilisation of the hops is affected by the boil volume, & your calculation does not allow for this.

Cheers Ross

[blandy]

p258 of "the complete joy of Homebrewing" by Charlie Parpazian is a hop utilisation chart. For a 45min boil with a boil SG of about 1.070, the table says the utilisation should be 29%.

I guessed the SG would be about that much for the boil, since it was about half the final volume.

How are others calculating IBUs?

Can someone show their working? If I'm getting this wrong I'd like to know why.

Thanks again everyone for checking my work so thoroughly, but all I've been told it that the answer's wrong, not how I SHOULD have calculated it. I'm very keen to learn and absolutly CRAVE constructive criticism.

That said, I've used this sort of calculation in my last 5-8 beers and they've tasted great, so I'm not worried about the beer, just the method.

[Ross]

Blandy,

Sorry, I don't have the formulea, i use beersmith. The progamme can be downloaded on free trial from http://www.beersmith.com.au.

If you boil your hops in 10L & then add 9L at the end, you won't get anywhere near as much bitterness as boiling in 19L from the start.
Your formulea doesn't appear to take this into account, so I'm assuming it only works for a complete boil & not when adding the extra as top up.

Try your formulea with the actual volumes used & then dilute the bitterness by the % of water you add at the end. See if this gives you a more accurate figure.

The low % beer you made would be extremely bitter with 50ibu's, so I'm guessing the actual ibu's you are acheiving, is giving a very nice balanced drink - Would just make sense to get actual IBU's straight, otherwise if/when you switch to full volume boiling, your beers will be over bittered.

cheers Ross

[chris.]

Blandy,

I don't believe your calculations are correct for a beer where you have added the final volume by top up. The utilisation of the hops is affected by the boil volume, & your calculation does not allow for this.

Cheers Ross

I too thought this at 1st but apon re-reading the formula I found

IBU = (weight in g)x(%utilisation)x(%alpha)/(final Volume)/(10)

I suspect the error has come about from the utilisation % used. How did you figure 29% out blandy? Calculating this figure is where your boil volume comes into play.

The final volume also needs to be taken into account for the dilution rate.

[blandy]

Hi everyone again!

I think I've found the difference in our calculations.

There is a hop utilisation table on HowToBrew, on this page:

http://www.howtobrew.com/section1/chapter5-5.html

But the values are pretty different to mine.

Does anyone know why these values are so different? eg my table has %U at 24% for whole hops (29% for hop pellets) for a boil of 45mins and SG(boil of 1.070)
On HowToBrew, the table rates it at 17.7%.

Using the HowToBrew chart, this gets an IBU of 22 for my Bitter, or maybe about 26 if you account for the fact that I'm using pellets, not cones.

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So which table do we use? Both Palmer and Parpazian are HUGE in the world of homebrewing. For these values to differ by this much (one is almost twice the other) is highly questionable. Obviously Beersmith is using something similar to Palmer's table.

All I know is that after racking today, my bitter tasted, .... well ... bitter! It's more bitter than anything else I've brewed before, and it's definately on the bitter end of all the beers I've had (although this was just warm straight out of the fermenter). I think I'll call the guys at G&G tomorrow.

[Tipsy]

So which table do we use? .

Hi Blandy,
I've been comparing promash and beersmith and was getting a huge variance in IBUs. I then used the How to brew table that you mentioned and got pretty close to the beersmith program.
FWIW I didn't have both the programs set to Tinseth

[Trough Lolly]

Guys,
Have another read of Ross's excellent advice. His important point is that you are calculating your hop utilisation based on the final volume of the batch - and you are not boiling with the final volume.

There are different utilisation calcs out there (Rager, Tinseth et al) but you need to take into account the volume of the solution that the hops are boiled in, not what you end up with in the fermenter / keg...

I've run your recipe through Promash and it supports the Beersmith calcs.

Cheers,
TL

[chris.]

Guys,
Have another read of Ross's excellent advice. His important point is that you are calculating your hop utilisation based on the final volume of the batch - and you are not boiling with the final volume.

Right. But the utilisation% in the calculation is based on the boil gravity.

The mistake is with the % utilisation figure used.

[Trough Lolly]

Agreed - and volume is a function of boil gravity...

[chris.]

I would say that boil gravity & volume are the factors of hop utilisation %

[Pale_Ale]

I would say that boil gravity & volume are the factors of hop utilisation %

That's what I thought. Assuming same gravity, volume affects utilisation independently.

[blandy]

If boil volume does affect utilisation, then it must not be that significant compared to the two other factors (boil SG and boil time) featured on both utilisation charts.

Basically the chart says that if you boil some hops (or pellets) for x mins at a SG of y, then the utilisation can be read off the chart.

The mass of alpha acid boiled into the wort must therefore be:
m(hops)x%AAx%U

Divide this by the final volume, and you get a concentration on a mass per volume basis.

So boil volume does not directly affect utilisation (at least not significantly), although the boil volume is indirectly picked up in the boil SG. (as in boil SG is roughly equal to (boil mass)/(boil volume))

At this stage I'm sure my method is correct, but I'm still wondering which utilisation table is correct.