IBU calculation

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HebridesRob

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As a Linux user, the only reasonable brewing app I have available is Brewtarget. I've noticed IBUs calculated by Brewtarget are significantly lower than those calculated by online tools, such as the one available through this forum.

eg. 27 litre boil; 22 litre batch; 1.050 OG; 50g hops; 7.5 alpha; 60 min boil...
Online calculator (Brewer's Friend) = 42.73 IBU
Brewtarget = 33 IBU

On researching the reason for this it appears there are three methods for calculating IBU based on research by Reger, Garetz & Tinseth. Brewtarget defaults to Tinseth's approximation while the online tool above must be using Reger's.
I found a setting to configure the method used so, In the interests of standardising my recipes with everyone else's, could anyone that designs their own recipes let me know what method their software uses?
I believe the most used software is Brewsmith, which appears to default to Tinseth. Is that right? Should we all configure our software to tie-in with Brewer's Friend?
 
Beersmith does indeed default to Tinseth although I can't find which measure Brewers Friend uses. Just because this site is sponsered by Brewers Friend doesn't mean that we should all configure all our software to tie in with it.

Surely, that's the whole point of Linux, choice.

Another Linux user.
 
My software, Brewmate, is set to provide an average. I can change it to Tinseth or Rager if I wish.

The problem with IBUs is that it's nothing like an exact science. The actual IBUs in a beer can vary enormously, depending on factors like the actual AA% of the hops as opposed to what they are labelled, at the time you use them, your water, and the methods and equipment you use. The yeast you use makes a difference too. I found this info about what commercial breweries do to be as consistent as possible:

"Commercial brewers measure the alpha acid content in a laboratory; then, after a few test batches in the pilot brewery, they adjust the hopping rate to the International Bitterness Units (IBUs) desired in the beer. To ensure consistency, large brewers purchase huge lots of hops and blend for uniform consistency throughout the year. Furthermore, virtually all large breweries blend beer to even out the fluctuations in bitterness from batch to batch, and add hop extracts to further adjust the bitterness."

From here: http://www.beer-brewing.com/beer_brewing/hops/hop_bitterness_beer.htm

When i use a recipe to create a beer, I rarely make it exactly per the recipe. I use my experience of making beer with my own method and decide how bitter I want it to be and base it on what has happened before as far as possible. I often want a different bitterness level to the recipe anyway. And I don't always get the bitterness I want. My last batch was a case in point, it turned out much less bitter than I wanted it. I was not careful enough, in that I used quite old hops and didn't adjust, I forgot to add gypsum, which accentuates bitterness, and I boiled for less time than usual! I thought I'd made the adjustment for that by adding more hops, but these three things conspired to reduce the bitterness quite a bit. In future I will try to use hops that I can trust for the bittering additions, as fresh as possible, keep to a consistent boil length and volume, and make sure I get my water treatment (if any) right, and consistent.
 
nbpicklesno2 said:
Beersmith does indeed default to Tinseth although I can't find which measure Brewers Friend uses. Just because this site is sponsered by Brewers Friend doesn't mean that we should all configure all our software to tie in with it.

Surely, that's the whole point of Linux, choice.

Another Linux user.
Click to expand...

Brewers Friend also uses Tinseth (says it at the bottom of the page). As for Linux, isn't he one of the kids Charlie Brown and Snoopy knock around with?
 
I've been looking at the 'storability' of different hops. On beerlegends.com and hopslist.com they give the AA% remaining in different hop varieties after 6 months storage, as a guide to how well each variety retains its Alpha acids. You can then put the % lost into this calculator and the age of the hops and get an estimated AA% figure for your hops, useful if your hops are not the most recent crop, especially.

http://brewerslair.com/index.php?p=brewhouse&d=calculators&id=cal16&u=eng

The hops that retain their AA best are Cluster, Summit, Apollo, First Gold, Phoenix, Magnum and Aurora. :-)
 
clibit said:
My software, Brewmate, is set to provide an average. I can change it to Tinseth or Rager if I wish.

The problem with IBUs is that it's nothing like an exact science. The actual IBUs in a beer can vary enormously, depending on factors like the actual AA% of the hops as opposed to what they are labelled, at the time you use them, your water, and the methods and equipment you use. The yeast you use makes a difference too. I found this info about what commercial breweries do to be as consistent as possible:

"Commercial brewers measure the alpha acid content in a laboratory; then, after a few test batches in the pilot brewery, they adjust the hopping rate to the International Bitterness Units (IBUs) desired in the beer. To ensure consistency, large brewers purchase huge lots of hops and blend for uniform consistency throughout the year. Furthermore, virtually all large breweries blend beer to even out the fluctuations in bitterness from batch to batch, and add hop extracts to further adjust the bitterness."

From here: http://www.beer-brewing.com/beer_brewing/hops/hop_bitterness_beer.htm

When i use a recipe to create a beer, I rarely make it exactly per the recipe. I use my experience of making beer with my own method and decide how bitter I want it to be and base it on what has happened before as far as possible. I often want a different bitterness level to the recipe anyway. And I don't always get the bitterness I want. My last batch was a case in point, it turned out much less bitter than I wanted it. I was not careful enough, in that I used quite old hops and didn't adjust, I forgot to add gypsum, which accentuates bitterness, and I boiled for less time than usual! I thought I'd made the adjustment for that by adding more hops, but these three things conspired to reduce the bitterness quite a bit. In future I will try to use hops that I can trust for the bittering additions, as fresh as possible, keep to a consistent boil length and volume, and make sure I get my water treatment (if any) right, and consistent.
Click to expand...

I was aware of all that. I was more interested in consistency between recipes, really. Individually, it doesn't really matter because one learns from experience but sharing recipes becomes a lottery if we're all working off different criteria, especially after factoring in the above.
 
Sorry! What I was trying to say was that IBUs are all over the place so trying to get a unified system on a forum is unlikely to lead to people creating the same beers even if everyone shared their software info, and knew what their software does.
 
clibit said:
I've been looking at the 'storability' of different hops. On beerlegends.com and hopslist.com they give the AA% remaining in different hop varieties after 6 months storage, as a guide to how well each variety retains its Alpha acids. You can then put the % lost into this calculator and the age of the hops and get an estimated AA% figure for your hops, useful if your hops are not the most recent crop, especially.

http://brewerslair.com/index.php?p=brewhouse&d=calculators&id=cal16&u=eng

The hops that retain their AA best are Cluster, Summit, Apollo, First Gold, Phoenix, Magnum and Aurora. :-)
Click to expand...

However bad they get, they'll be way better than the hops I used to buy 30 years ago, which were yellow and papery. I was using 2.5-4 oz (70-100g) to make 5 gallons of bitter. One of the things I was surprised at when I recently returned to beer making was how few hops are used in modern recipes.
 

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