Pre-Boil Vol <-> Bitterness

Hi!

I'm new to this forum, to brewing and to BeerSmith, so I hope you'll bear with me if I'm doing the obnoxious newbie thing and asking questions to which I should already know/easily find the answers. In that case, please accept my apologies beforehand!

So, to business:

Background: I'm trying to figure out the software, which seems just amazing, but would like to know that it works for me before buying it. I'll be boiling (from extract) in a 10 L (2.6 Gal) pot, so I chose the 11.4 L (3 Gal) pot in the program as it was closest. Now, trying to make a 22 L batch (5.8 Gal), the estimated pre-boil volume is automatically set to 11.9 L, which there obviously isn't room for in my pot. Unticking "Calc Boil Vol" lets me enter my own value there, but if I go for say 8,5 L, the "Bitterness" gets messed up. (From 35.8 to 25.7 IBUs.)

Am I misunderstanding something here? Is the bitterness really affected so much from a slightly smaller amount in the boil, and slightly more water added later to the final wort size? Or have I misunderstood the concepts here in some way?

...

Also, on another note, is there a way to export the inventory so I can share it with my brewing pal? (And my other computer.)


Thanks in advance for any replies you might have for me!


Best regards,

Kalle

Its not strictly about the volume, but rather its about the wort concentration.  If you just reduce the volume but keep the grains and extract the same the wort concentration will increase. 

Your "slight" change from 11.9 to 8.5 is actually quite large from a percentage point of view.  That is a 28% decrease in boil volume.  Which will result in a 28% increase in wort concentration. 

Bitterness comes from isomerized alph-acids (AA) which difuse into the beer from the hop material.  These AA diffuse into the beer slower at higher wort concentrations.  So, the more concetrated the boil the more lower the resulting bitterness will be for the same amount of hops.  28% is a big change in concentration and will ABSOLUTELY cause a noticeable reduction in bitterness, if you don't compensate with a larger quantity of hops. 

The maximum attainable IBUs, IN THE BOIL, is ~100 IBUs.  When you do a partial-boil, you can still only disolve 100 IBUs into the boil.  But, then when you dilute the wort for in the fermenter, you dilute the IBUs also.  So, if you reached ~100 IBUs (maximum AA solubility) in a 2.5 gallon boil...and then double the volume (to 5 gallons) in the fermenter you will have a 50 IBU beer. 

If you make your boil volume an even smaller fraction of your batch size, you will further reduce your maximum attainable, finished beer IBU level.  It should be noted that 100 IBUs is pretty hard to actually hit; it required LOTS of hops and a LONG boil time. 

Finally, BeerSmith does NOT implement this maximum solubility limit.  Beersmith will happily calculate a 250 IBU beer (say...Pline the Elder).  But, the resulting beer will not ACTUALLY have that much bitterness.  If you took it to a lab and had it analysed, it would be between 90 and 100 IBUs...which is the case with Russian River's Pliney the Elder (and the clone recipe which I'm brewing this weekend).

To your second question:  Yes, there is a way...see here in the help file for how:

http://www.beersmith.com/help2/importing_and_exporting_files.htm

Thanks a lot for the thorough answer! I realise now that I chose the wrong forum, since this wasn't a question about the software but rather about brewing in general. My bad, I didn't know better!

I didn't know about the wort concentration's effect on the hops. (But the part about diluting the bitterness of course makes perfect sense, now that I'm reading it!) Would adding, say, half of the dry extract after the bowl help?

Also, for calculation purposes, does Beersmith show the gravity and estimated IBU of the concentrated wort somewhere, if I choose to dilute the wort later?

And, yes...a larger pot is on the wish list. I'd just want to get at least one brew going before making any new investments. Who knows, I might be perfectly hopeless at this!

Again, thanks a lot for your help and your patience!

Best,

Kalle

Adding the dry extract after the boil would risk infection.  Right idea...too much risk. 

I'm not very familiar with how beersmith handles partial boils and late-extract additions.  I haven't brewed that way since 2003.  I know it DOES....I'm just not familiar with exactly what the limitations are.

Sure it makes sense to use the pot once, before buying a bigger one.  We are all hopeless....hopelessly addicted to the hobby....that is.

Welcome to the addiction!

We are always here to help.  Nothing wrong with the forum you chose to post in. 

PS:  www.thebrewingnetwork.com  enjoy.

Hi Foodhead, hi Kalle,

I am new here on the forum as well and learned already a lott. I even from time to time could contribute.
Welcome to the forum!
Regards,
Slurk

Thanks again!

After playing around with Beersmith a while, I've managed to move half of the extract towards the end of the boil. Five minutes should take care of the risk of infections, right?

Now that I understand the effects better, I feel more confident in adjusting the recipe. But, one thing I'm wondering now is... Does the concentration of the wort mainly affect the bitterness from the hops, or the taste and aroma as well in a similar way? If I would double the amount of hops to compensate for a more concentrated wort, would this only be applicable for the bittering hops at the beginning of the boil, or the taste and aroma hops later on as well?

I'll probably find a way to work around the concentrated wort, by adding some of the extract later and borrowing a slightly bigger pot, but I'd still like to understand this fully.

And thanks for the warm welcome! I'm learning at an amazing pace here, and hope I'll be able to contribute myself in due time!

Best,

Kalle

Yep, that's a good plan.  Quite common.

You are correct, the concentrated boil will affect the bitterness more than the aroma/flavor additions.  Flavor and aroma are more influenced by the mass of the addition.  In other words, 5 oz at 10 AA% is not the same as 10 oz at 5 AA%.  So, when planning these additions, think in terms of weight, not AA%.  These are not really affected much by wort concentration. 

So, yes increase your bittering addition to compensate for the wort concentration, and leave the flavor / aroma additions alone (or increase only slightly).  Some trial and error will be required because your exact concentrations, and boil "dynamics" will affect things more than the same variations on the full-boil level.

On a side-note, how did the pliny clone turn out?  I am looking at one myself and beersmith is calculating at 250.4 IBU.  I was anticipating the same over-calculation as you discussed, but I haven't made anything with this large of a hop-bill before to know if it would in fact even out. 

Its clarifying in the primary as we speak.  Its quite amazing even in as samples from the fermenter.  I still have another week or so of clarification, and then into a keg for two weeks of dry-hopping.

Update:

I got my hands on a larger pot in the last minute, and managed to boil the whole volume.

It now seems to have fermented out, but the SG appears to have landed at 1019, which is quite a bit higher than anticipated. (OG was 1057.) I made a starter on a Whitbread Ale smack pack from Wyeast and it has been fermenting in around 17 degrees C (62 F), which is at the lower end of the spectrum. (It's been sitting there for 1,5 week so far.) What is more likely to have caused the quite high SG at this point? A bad starter? Too low temperature? Should I move it up to room temperature (22 C/71 F) for a while, to see if the fermenting starts again before bottling?

Thanks in advance for any answers you might have!

/kalle.

62 is pretty low. My money is on temperature.  I would swirl the carboy or bucket to get the yeast back into suspension and raise the temp to 68 or so. 

If you have temp control then generally it work well to have a rising profile as th fermentation begins to slow. Once I see the fermentation is slowing down I begin raising the temp by 1 degree per day.

Update:

I gave the fermenter a light swirl in the basement, to see if that did the trick, but apparently it didn't. So I took it up to the flat, where it's considerably warmer, for dry hopping and to see if there was any fermentation left in it. ...and after just a few days it's down to 1014, so apparently it worked!

It also both tastes and looks great! (As you can probably imagine, I'm immensely excited about this, since it's our first try at brewing ever.)

Thanks again!

/kalle.

Another update: It tastes great!

Thanks a lot for your help.

/kalle.

Foodhead congratulations! Nice label by the way...
Regards,
Slurk