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IBU question
I was checking out a beer calculator online to see if my beer was coming up close to what I wanted, (wasn't able to get an OG because my hydrometer broke during the boil). One thing I noticed was when I changed the setting from a 4 gallon boil to a 2 gallon boil, the IBU's changed from 26.2 to 10.6...?...has anyone heard that moving to a partial boil dramatically lowers your IBU's? I only have a 12 quart pot which allows me to boil 2 gallons + ingredients and then pour into 3 gallons of cold water to make my wort. I was going for about 25 IBU's which the calculator said I got to but when I changed it to a 2 gallon boil it told me I only had 10 IBU's which would be way to low for the sweetness of the beer I'm brewing.
Does this make sense? If you're boiling the same ammount of hops for the same batch size, why would the boil ammount affect your final IBU's that much?
I didn't change the batch size on this calculator, just the boil size. Any thoughts?
Are you sure you plugged everything in the same both times? Try this website. I have found it to be very accurate.
http://beertools.com/html/calculator.php
If you still get the same result then there must be something to it, but I have a feeling you miss entered something in one of the times. The only other thing I can think of is that your are using a whole lot of weak hops and there is not enough water to absorb into all the hops and thus the bitterness is not being abstracted properly. But you would need a LOT of hops for that to happen, and with 26 IBS, you would need a very very mild hop to need that large of a quantity of hops where saturation starts to be a problem.
Maybe someone else can explain it better than I can, but I believe that your calculator is right. The smaller the boil, the less hop utilization you get. I haven't done a partial boil in quite some time, so I don't remember just how dramatic the drop in utilization is, but you usually need to add more hops to make up for it.
The ability to isomerize alpha acids is concentration and solubility dependent. So when you take a 4 gallon recipe and reduce it to 2 gallons you halve the amount of water available to solublize the acids, and you double the amount of sugar concentration. The increase in concentration of all things in the water (sugars, alpha, minerals etc etc) prevent the additional isomerized stuff from staying in solution. So the alpha is like an insoluble solid in caught in the hot break and protein mess in the bottom of the pot per se.
So yes your calculator is right. Less water usually means less IBUs when all other things are being held constant (i.e. the amount of extract being used and hops applied).
Well, I guess I'm just going to have to take a taste and maybe add some dry hops it it needs some making up for. I boil 2 gallons with the lid on so there is little reduction overall. I used 1 oz of northern brewer for 60, 1/2 oz tettenger for 15 and the other 1/2 oz of tett for 2 min. Maybee some more of the Tettenger. Although the IBU's are probalby more associated with the NorthBrewer that boiled for 60 min. I'm just going to pop the stopper off and take a sample.
Thanks for the feedback everyone, and the detailed explanation Brewchez. I'm sure this will be usefull knowledge for not only me but other just starting home brewers.
To solve your IBU problem simply boil 1/3 to 1/2 of your total malt bill for the full 60 min. and then add the balance for the last 20 minutes. This is refered to as the late extract addition procedure. Doing a dry hop addition will add no IBU's, incase you thought otherwise. Also you should not boil with your lid on the kettle/pot as that there are nasty flavors (like DMS - Dimethyl Sulfide) that are driven off during the boil that leaving the lid on will simply re-introduce these back in. Hope this helps.
Hmmm, that's an interesting thought. Would that mean since I used 2 can's of Munton's Amber LME I'd boil 1 can and add another oz of Northern Brewer at 20 min, then add that to the batch in the secondary? Perhaps boil with an additional gallon of water? I've never heard of this technique before...granted I'm newer to brewing beer. Thanks for the tip Brewmando, though as a novice I could use just a bit of elaboration. Don't want to make too many assumptions, I did, however, understand the dry hoping wouldn't add IBU's, those would be aroma hops, yes? Would doing this spark up some new fermentation? Would I need to pitch some new yeast?
On a side note, I used the carboy thief to take a sample and it is a bit sweet tasting and could probably use a little more bitterness...but not terrible. I am trying for a clone though and would like to get it right, but it may be too late for that and need to try on another batch down the road. But if I completely understand this "late extract addition" I'd like to consider trying it, if for nothing else education's sake.
If you're willing to type just a bit more, Brewmando, I'm interested in going that route.
Oh wait, I think I understand, I did this with the Heffeweizen I did last time (per instructions in the ingredient kit [tru brew hefeweizen]), on the next batch I brew I don't add all the extract at once but like you said in the last 20 min! Brilliant! I wondered why the instructions called for that. Unfortunately this beer is already in the 2ndary, so it will have to be on the next batch. But I will definately do this method in the future as like I said, I only have a 12 quart pot and cant drop $130 on a 24 quart stainless pot right now.
Thanks so much Brewmando! I hope other newbies check out this post and learn from my mistake.
Yep, just like in the Tru Brew Heffe kit! No need to up the amount of bittering hops, just reducing the amount of soluables in the boil (but you DO need some for proper hop utilization!) will increase the level of bitterness and get it closer to the proper levels. A lot of extract kits are geared towards folks like us who boil inside, on our kitchen stoves. I myself have two 4 gallon stock pots that cost me only $4 a piece at a local grocery store. I can also do all grain outside or even use both my pots inside and just split a recipe between the two pots for a split/full boil. I do have a fairly powerful stove - 10 min. to steeping temps and about 20 to a boil for 3.5 gallons. I will try and find an informative article on the late extract addition info and post a link.
Sounds great, if this doesn't turn out exactly like I want it to I'll just call it "Strong & Sweet Amber Ale" 
. Regardless of the bitterness I should end up with about 7.3% ABV. I'll just keep it extra cold.
Are you using any grain in this recipe? If so like in a partial-mash, mash the grains then continue with your boil (leaving the lid off of course) Then add all your extract at your 10 minute mark. This will kill the boil. Turn off the flame stir in the extract really well and turn the flame back on.wait till you have a boil going again and restart the clock. That is my procedure for doing late extract brewing. You want the extract in the boil for at least some of the time to sanitize it just make sure to turn the flame off and stir it in really well or else it will caramelize and or burn to the bottom.
Hope this helps
ID
Just specialty grains in this batch (crystal). But I like that idea. I'm definately going to be doing this recipe again with the change of doing the late extract addition. Thanks everyone for the feedback it's been most informative.
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