18 replies to this topic

[johnpreuss]

Ok so today was going along as good as a brew day could. No real problems just chugging along. Then I add my 15 minute hop addition and suddenly the gas goes. It takes me 15 minutes to run and get a new tank, and another 10 min to get her up to a boil again. I let it boil for another 10 minutes before I kill the flame and add the flame out addition. I have NO IDEA how to figure IBUs on this. Heck, I just popped the top on the fermenter to see if I had a krausen and POW hops to the face. I was trying for an APA around 36 IBU but I think I got a low OG IPA. Here's the original schedule and what I figured for IBUs:1 oz Target 8.6%AA 60 min.5 oz Williamette 4.8%AA 15 min.5 oz Cascade 5.4%AA 15 min.5 oz Williamette 4.8%AA Flameout.5 oz Cascade 5.4%AA Flameout36IBUsI'm guessing it's going to fall in the mid 50s but can anyone help me out???

[Stout_fan]

I'd guess you have two bittering additions and one aroma.1 oz Target 8.6%AA 80 min.5 oz Williamette 4.8%AA 35 min.5 oz Cascade 5.4%AA 35 minPromash should figure this out for you.

[Beejus McReejus]

Sounds like you made beer.

[jasonrobertcohen]

John,I understand what you're trying to figure out. Because the middle 25 minutes of that ordeal was not during a rolling boil, you're not sure how to discount the time spent with hops in hot* wort. Frankly, there will be two problems in determining this. For one, you're not sure exactly what the temperature schedule during the 25 minute cooling and heating times. Secondly, I don't think there is much research into what the IBU contributions are at temperatures in those ranges. Trying to calculate this out without enough empirical results to model it after would be futile. I'd take an approach similar to stout_fan, but probably wouldn't just add all the time in as if it were at the normal boil temperature. Perhaps a 20-30% reduction (on the time), but I really am just throwing darts.jrc

[johnpreuss]

Sounds like you made beer.

LOL thanks, sometimes you just need that response. I get overly into what is suppose to happen and what really happens during the brew day I forget what the goal is. Make beer.

[jayb151]

I say, wait to taste it!Is it really that important that you get the exact IBUs? I know you want a guess, but I would just figure that you shot for 36 IBUs but it's gonna turn out with more. If I HAD to take a guess, I would say your 60 min addition turned into a 90, which isn't that much different, and the 15 turned into a 30. Even though you're not boiling, you're dissolving bitterness into the liquid.

[lowendfrequency]

Correct me if I'm wrong but it is my understanding that isomerization of alpha acids will continue to occur until your wort drops below 100 degrees F. I would have just waited the 15 minutes (since my wort would still be hot), dropped in my flamout hops and started chilling right on schedule, sans flame. Granted, your utilization might be lower during that last 15 minutes, but how many IBU's were you really going to squeeze out of those late additions hops in the first place (unless you were hopburtsing)?. It takes only 30 minutes of boil to get a 90% isomerization rate from your bittering hops, so I wouldn't worry about your 60 minute addition at all.

[gnef]

I think you will be fine, but if you want to be sure this doesn't happen again, get a spare tank, or two!I have 5 propane tanks, one I keep on the grill. So I keep 4 propane tanks for brewing. Today, both tanks went dry - I could tell they would when I first hooked them up, so I just paid attention to when they went empty, and just hooked up the spare tanks. I already got them refilled, so I have nothing to worry about for a while again.I have considered getting a 100# tank (I know blktre and others on this board use them with great success), but that is just too heavy for me, and I don't have a truck to get it filled, and I would have to get extension hoses to the burners. If your setup works well for the larger tanks though, it may be a consideration for you so you don't have to get propane as often.

[zymot]

The beer you made will be better.I promise.How do I know?Because now you have a story to go along with the beer you brewed.A beer and a story is better than just a beer.

[johnpreuss]

I think you will be fine, but if you want to be sure this doesn't happen again, get a spare tank, or two!I have 5 propane tanks, one I keep on the grill. So I keep 4 propane tanks for brewing. Today, both tanks went dry - I could tell they would when I first hooked them up, so I just paid attention to when they went empty, and just hooked up the spare tanks. I already got them refilled, so I have nothing to worry about for a while again.

I have a spare... it was empty... Yeah I was kicking myself on that one.

The beer you made will be better.I promise.How do I know?Because now you have a story to go along with the beer you brewed.A beer and a story is better than just a beer.

Ok, I vote Zymot the philosopher brewer. Every time I get all bent out of shape he comes up with this stuff. It's like I forgot Rule #1: RDWHAHB. Rule #2 being Sanitize sanitize sanitize. It will be beer. Hoppy good beer.

[djinkc]

My vote is you'll probably be fine. Just one of those beers that will be hard to duplicate - so it's guaranteed to be great.OTOH this is why my brewery is all electric I always keep a FULL propane tank around for the few times I use the propane burner.

[Big Nake]

Correct me if I'm wrong but it is my understanding that isomerization of alpha acids will continue to occur until your wort drops below 100 degrees F. I would have just waited the 15 minutes (since my wort would still be hot), dropped in my flamout hops and started chilling right on schedule, sans flame.

This is interesting. I plan to brew tomorrow and I only have 1 propane tank... when it's empty, I run it to the local hardware store and replace it. My tank is currently low and I just realized I could have this same problem tomorrow. Interesting that if I only had 15 or 20 mins left in the boil and the gas went out that I might be able to just leave the pot for the remainder of the hour and then chill. I never considered this. These trips to the store to replace the tank are always hilarious too because I'm behind an old lady in line who's buying a pack of gum and looking in her purse for the extra 11¢. DOH!

[zymot]

Ok so today was going along as good as a brew day could. No real problems just chugging along. Then I add my 15 minute hop addition and suddenly the gas goes. It takes me 15 minutes to run and get a new tank, and another 10 min to get her up to a boil again. I let it boil for another 10 minutes before I kill the flame and add the flame out addition. I have NO IDEA how to figure IBUs on this. Heck, I just popped the top on the fermenter to see if I had a krausen and POW hops to the face. I was trying for an APA around 36 IBU but I think I got a low OG IPA. Here's the original schedule and what I figured for IBUs:I'm guessing it's going to fall in the mid 50s but can anyone help me out???

You changed 15 minute additions into something closer 50 minute additions.I will assume/guess on OG of 1.050.Original recipe: 41.7 IBUAfter (lack of) fire drill: 52.2 IBUAbout 10 IBU more. Seems like alot. But it probably is not a major difference. Little less hop flavor, little more bitterness. There are many variables in play, they only time you will notice is when you are thinking about it.zymot

[jayb151]

Ken,Just remember too that if you're not boiling, you may be allowing DMS to form if it's still hot. Now, If you boil for 90 minutes (like I believe you do) then you'll be fine.

[ChicagoWaterGuy]

Ken,Just remember too that if you're not boiling, you may be allowing DMS to form if it's still hot. Now, If you boil for 90 minutes (like I believe you do) then you'll be fine.

Shorter boils and DMS is more of an issue with pilsner malt due to higher levels of SMM.

[Big Nake]

It's possible that I may shun pilsner malt altogether from now on. There was talk in my "hazy light-colored beer" thread about pilsner malt having more protein in it and that using standard 2-row would be easier. I have used a lot of pilsner malt and also 2-row in "gold lagers" and can't really tell much of a difference with the exception of a few beers here or there. As a result, DMS may not be a problem for me anymore! Cheers.

[AiredAle]

A rule of thumb in chemistry is that for every ten degree Celsius drop in temperature, the rate of a chemical reaction drops by 50%. So I would not assume that the isomerization rate is the same in boiling wort as in cooler wort. I would guess that over the 35 or so minutes the wort was cooling and then reheating that the temp dropped to about 170 or so, and then went back up to boiling. So the average temperature was say, 190. That's about 10 degrees Celsius below boiling. I'd assume a 5 IBU increase in bitterness, not 10 as Zumot suggested. You will get more hop character and aroma though, and this may dominate any changes from what you expected. The beer will be fine, enjoy it in it's time.

[Starderup]

Ok so today was going along as good as a brew day could. No real problems just chugging along. Then I add my 15 minute hop addition and suddenly the gas goes. It takes me 15 minutes to run and get a new tank, and another 10 min to get her up to a boil again. I let it boil for another 10 minutes before I kill the flame and add the flame out addition. I have NO IDEA how to figure IBUs on this. Heck, I just popped the top on the fermenter to see if I had a krausen and POW hops to the face. I was trying for an APA around 36 IBU but I think I got a low OG IPA. Here's the original schedule and what I figured for IBUs:1 oz Target 8.6%AA 60 min.5 oz Williamette 4.8%AA 15 min.5 oz Cascade 5.4%AA 15 min.5 oz Williamette 4.8%AA Flameout.5 oz Cascade 5.4%AA Flameout36IBUsI'm guessing it's going to fall in the mid 50s but can anyone help me out???

The problem is going to be when you try to duplicate this recipe.

[johnpreuss]

A rule of thumb in chemistry is that for every ten degree Celsius drop in temperature, the rate of a chemical reaction drops by 50%. So I would not assume that the isomerization rate is the same in boiling wort as in cooler wort. I would guess that over the 35 or so minutes the wort was cooling and then reheating that the temp dropped to about 170 or so, and then went back up to boiling. So the average temperature was say, 190. That's about 10 degrees Celsius below boiling. I'd assume a 5 IBU increase in bitterness, not 10 as Zumot suggested. You will get more hop character and aroma though, and this may dominate any changes from what you expected. The beer will be fine, enjoy it in it's time.

I think you might be pretty close here. I just bottled it tonight and the hydro sample wasn't overly hoppy. But like others have said there will be no duplicating this recipe.