Adding IBU's after brewday

[Dancing Camel]

Is there any formula for bumping up the bitterness on a beer post-fermentation?

David

[Fred Scheer]

Is there any formula for bumping up the bitterness on a beer post-fermentation?

David


HI David:

In order to help you, please let me know how
do you calculate your BU's b4 fermentation.
Also, do you measure your BU's or IBU's with
a spectrophotometer or any other lab devise???

Fred

[Dancing Camel]

Measuring after brewing is based only on taste. Before brewing I primarily rely on Promash to tell me what IBU's I should be getting. Not too sophisticated. What I'm looking for was a way to safely add bitterness to beer after it's already been fermented since scaling up recipes has been a less than precise science.

David

[tylerpeters]

before brewing you should be able to be able to figure your IBU by simply using the following formula. this may help give a better idea than relying on promash for everything.

Predicted IBU = utilization% x alpha acid% x oz x 7490 / gallons

which is derived from...

IBU = utilization% x alpha acid% x (oz x 28,350 mg/oz) / gallons x 3.785 L/gal

utilization% x alpha acid% x oz / gal x 28,350 mg/oz / 3.785 L/gal

utilization% x aplha acid% x oz x 7490 / gallons

for calculating adding IBU's to the beer after fermentation - my best guess would be to figure out what you want for your target IBU and then go this route...

Oz of Hops = gallons x desired IBU / utilization % x alpha % x 7490

or

Mg of hops = liters x desired IBU / utilization % x alpha % x 7490

but remember that you'll need to figure out a way to determine the utilization percentage without heating. also, you'll need to take your hop storage index "HSI" number into account if you've had these hops sitting around for a month or two due to the natural degradation of the alpha acids.

hopefully that is a start. good luck.

[tarmadilo]

To get back to the original question, it's extremely difficult to take a beer that you've already brewed and make it more bitter. You could perhaps boil some hops in a measured amount of water, making a hop tea, and add that to the beer, but it'd be awfully tough to get it right.

A somewhat easier way would be to brew another batch of the same beer, except with a significantly higher IBU, and blend the two. Sure, you'd end up with twice as much beer as you originally wanted, but it shouldn't be hard to figure out how to hit your target IBU figure...

Cheers, Tim

[tylerpeters]

i forgot to add into my other post that there are alternatives to attempting to add bitterness after fermentation. there are two methods that i can think of to add bitterness post fermentation.

1) dry hopping - wont add much bitterness, but will add to aroma if done properly

2) hop extract - you can significantly alter your bitterness but also your entire flavor profile. these are extremely concentrated and can alter your head retention if not used properly.

cheers

[Dancing Camel]

I admit that I use Promash as a crutch. It'll be good to have a formula that I can check the calculations myself.

Instead of using water I was actually thinking of pulling off about 10 gallons of the beer and boiling it up with some extra hops, then throwing it back into the batch. I'd prefer not to add water though I suppose a few gallons won't hurt. Any problems with boiling up the beer instead?

David

[bbrodka]

Any problems with boiling up the beer instead?

David

introduction of unfermented sugars

[tarmadilo]

I admit that I use Promash as a crutch. It'll be good to have a formula that I can check the calculations myself.

Instead of using water I was actually thinking of pulling off about 10 gallons of the beer and boiling it up with some extra hops, then throwing it back into the batch. I'd prefer not to add water though I suppose a few gallons won't hurt. Any problems with boiling up the beer instead?

David

I'd think the only real problem would be hitting your target IBU number. Heck, I'd probably just make up a new name for the beer and sell it as a special batch! :D

Cheers, Tim

[RaySherwood]

Any problems with boiling up the beer instead?

David

If you do decide to pull off some beer, you'll need to add some water back to it to keep the gravity the same, and I'd recommend filtering it to avoid any cooked yeast flavors.

You might also just grab some wort off another similar batch and make a hop tea from that.

Good luck,
Ray

[jagg1]

try iso-alpha acids of a known concentration. Some of the big brewers add/adjust their IBU's before and/or after fermentation. Do not forget that 1 IBU equals to 1mg alpha-acids/ lt beer.

[Beersmith]

You can purchase isomerized hop extract (Iso-Hop Extract) to add bitterness at any point in the process. In particular, I think it iwould be handy for adding bitterness to finished beer and in recipe experimentation. I have only used it once, but it did work like a charm. Ask your hop supplier about iso-extracts, I believe several of the larger suppliers do produce them.

[Sir Brewsalot]

Start-up formulation is fun, isn't it? I had the opposite problem with my batch #1 a little less than 2 years ago - WAY too bitter. My approach was very low-tech:

I elected to set it aside (I had the tank space), try the same brew again with changes, and it was spot on. I then brewed #3 as the "anti-batch" to #1 - using #2 to set the midpoint target (ignoring non-linear hop utilization). I tested various ratios of the two batches to see what gave the best result, and had a couple kegs of underhopped beer leftover.

So to get the blend to come out, I think batch #3 required only 4 oz of bittering hops in a 7bbl batch. (Told you #1 was bitter!)

If you can afford to make three batches of one beer, it's my recommendation. If not, make up the tea with beer as make-up. The amount of yeast is insignificant in my opinion. Make more than you'll need, blend in some (maybe bubble CO2 up through the tank to agitate), taste...add more if needed.

Congrats on getting started!
Cheers,
Scott

[davidmeyers]

Getting back to the earlier part of the thread. Just wondering, how you destermine your utilization. I mean, what is that number actually based on? I have some figures that were handed down to me by the previous brewer, but they seem to be quite arbitrary. 30% @ 90 minutes, etc. How can I go about calculating these figures for myself?

[hallertau2000]

Call Yakima Chief and ask for 10%Tetra Hydro Iso Alpha Acids,comes in liters
Works very well for adding IBU's post fermentation/filtration
The literature will give you a ball park dosing rate

later James