How much less hops...

[aekdbbop]

Ok, my recipie called for 3/4oz at 60min, and 1/4oz at 15.

That is for a partial boil.. what changes should i make for a full 6.5gallon boil?

 

[zoebisch01]

Ok, my recipie called for 3/4oz at 60min, and 1/4oz at 15.

That is for a partial boil.. what changes should i make for a full 6.5gallon boil?

First you need the OG of the first boil and the volume of that boil. You then need to calculate the boil gravity when it is diluted. Then you need to reapply the utilization equations. I'll take a stab at it if you post those numbers and what the AAU of the hops is. Actuall now that I think about it, just need the total points and AAU.

 

[aekdbbop]

1.044 @ 5.5 gal

cascade hops@ 7.5%aau

i dont know what the boil gravity is, or how to find that out... i havent started my boil yet.

 

[zoebisch01]

1.044 @ 5.5 gal

cascade hops@ 7.5%aau

i dont know what the boil gravity is, or how to find that out... i havent started my boil yet.

How it works is, you take the approximate points say you are using LME @ 37 pppg. And you add 5 lb to 5 gallon....that gives you 37 * 5 lb / 5 gal = 37. But if you are using 5.5 that would be 37 * 5 lb / 5.5 gal = 33.6 (pts). You can then use that number and look up in a chart (or use an equation) like those found here:

http://www.howtobrew.com/section1/chapter5-5.html (Scroll down)

to find out what your utilization factor would be. You don't really need the AAU number for the calculations, but in order to hit the same IBU it is helpful.

 

[zoebisch01]

Are you saying that the projected starting gravity is 1.044 at 5.5 gallons and you want to increase the volume of the boil to 6.5 gal? If this is case then you can scale the points like this:

5.5 gal / 6.5 gal = 0.84 (this is a proportional factor)

Then you take your points and scale them, like so:

44 * 0.84 = ~37 points or 1.037.

So if you look on that chart you can kind of get an idea what happens to the utilization in the boil with the 1.044 and the 1.037 gravities.

 

[aekdbbop]

i am not sure, it says that once at 5 gallons in your fermenter, the OSG should be 1.044

It is telling me to boil 2.5 gallons with 3/4oz at 60 and 1/4oz at 5min... so i wanna know how much to use for 5.5 gallons instead of 2.5

 

[zoebisch01]

Ok, let me run the numbers.

 

[aekdbbop]

thanks.. i suck at math..

 

[RoaringBrewer]

I ran the numbers through BeerSmith for you...

For 2.5 Gallon Boil I came up with 12 IBU range for the hop schedule given (7.5AA hops, .75oz for 60 and .25 for 5)...

If you boil 6.3 Gallons (recommended for 5.5 gallon batch), it bumps the IBU to 24ish IBU range. If you want a hoppier beer than the original recipe suggests, you could keep the same hop schedule and just up the boil (I personally don't think 25IBU and 1.045OG is out of balance at all...).

If you want to keep the same exact IBU as the recipe planned, then you need to cut back on the hops to around .5oz (.4x or something exactly) or so for 60 minutes, and keep the same addition at 5 mins.

 

[zoebisch01]

So the IBU should be at 11 - 12 ish for the 2.5 gallon boil.

You arrive at it like this:

You have 5 gallons with a gravity of 1.044 , but you are halving that volume...so this increases the boil gravity by a factor of 2:

5 gal / 2.5 gal = 2

2 * 44 = 88 = 1.088 boil gravity.

If you plug in 2.5 gallons of volume and a gravity of 1.088, for that hop schedule using the equations found on the page I posted (Palmer) you get somthing in the neighborhood of 13 to 14 IBU. Then you need to figure out the new boil gravity:

5gal / 5.5 gal = 0.90

0.9 * 44 = 40 = 1.040 boil gravity.

So running this through the equations gives you an IBU of about 20. It is kind of hard to give exact numbers for the 2 different schedules without doing a little more work, but if you do a 70% decrease on both:

0.525 oz @60 minutes
0.175 oz @5 minutes

that gives you around 14. You could probably round it just fine to make the measuring easier or use a gram scale.

15 gm @60 minutes
5 gm @5 minutes

Hope that helps.

 

[aekdbbop]

thanks it does.. youre the man.

 

[RoaringBrewer]

So the IBU should be at 11 - 12 ish for the 2.5 gallon boil.

You arrive at it like this:

You have 5 gallons with a gravity of 1.044 , but you are halving that volume...so this increases the boil gravity by a factor of 2:

5 gal / 2.5 gal = 2

2 * 44 = 88 = 1.088 boil gravity.

If you plug in 2.5 gallons of volume and a gravity of 1.088, for that hop schedule using the equations found on the page I posted (Palmer) you get somthing in the neighborhood of 13 to 14 IBU. Then you need to figure out the new boil gravity:

5gal / 5.5 gal = 0.90

0.9 * 44 = 40 = 1.040 boil gravity.

So running this through the equations gives you an IBU of about 20. It is kind of hard to give exact numbers for the 2 different schedules without doing a little more work, but if you do a 70% decrease on both:

0.525 oz @60 minutes
0.175 oz @5 minutes

that gives you around 14. You could probably round it just fine to make the measuring easier or use a gram scale.

15 gm @60 minutes
5 gm @5 minutes

Hope that helps.

This is why I paid $19.95 for beersmith software. We basically got the same answer and I spent literally 30 secs. Nice job on the manual math, but thats not for me...

 

[zoebisch01]

This is why I paid $19.95 for beersmith software. We basically got the same answer and I spent literally 30 secs. Nice job on the manual math, but thats not for me...

Lol. I have a spreadsheet and all I do is type in what I want, but it is not set up for doing the conversions (yet) as I don't do extracts or PM's. It was a good sanity check though hehe.

 

[zoebisch01]

Just wanted to clarify...it isn't set up for scaling batches because I tailor my process to 7 gallon boils, that is what I shoot for every time...plus I figured, as long as I am doing it I might as well show the calculations for others who want to follow the method.