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Tinseth Hop Calculation Help
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Topic: Tinseth Hop Calculation Help (Read 2883 times)
NorthernIke
Cellarman
Posts: 51
Tinseth Hop Calculation Help
«
on:
January 16, 2010, 07:50:56 PM »
I'm sick of looking up hop utilization numbers when building recipies. I use a spreadsheet that I built for my brewing "software".
I need some help building an equation in Excel. I use the Tinseth formula, and on his page on of the stated factors is "boil time factor". This is determined by this equation:
The Boil Time factor accounts for the change in utilization due to boil time:
Boil Time factor = 1  e^(0.04 * time in mins)

4.15
My question is what does "e" refer to in the above equation? How do I program this into Excel?
Here is Tinseth's page where I got the formula:
http://realbeer.com/hops/research.html
Thanks!
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NorthernIke
Cellarman
Posts: 51
Re: Tinseth Hop Calculation Help
«
Reply #1 on:
January 16, 2010, 07:54:16 PM »
From Wikipedia:
http://en.wikipedia.org/wiki/E_%28mathematical_constant%29
The mathematical constant e is the unique real number such that the value of the derivative (slope of the tangent line) of the function f(x) = ex at the point x = 0 is exactly 1.[1] The function ex so defined is called the exponential function, and its inverse is the natural logarithm, or logarithm to base e. The number e is also commonly defined as the base of the natural logarithm (using an integral to define the latter), as the limit of a certain sequence, or as the sum of a certain series (see the alternative characterizations, below).
e is one of the most important numbers in mathematics,[2] alongside the additive and multiplicative identities 0 and 1, the constant π, and the imaginary unit i. (These are the five constants appearing in one formulation of Euler's identity.)
I guess I'm no Mathlete! I'm going to try and plug this into Excel...maybe it's smarter than me...
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NorthernIke
Cellarman
Posts: 51
Re: Tinseth Hop Calculation Help
«
Reply #2 on:
January 16, 2010, 08:12:42 PM »
Thanks to Wikipedia..."e" can be described as:
2.71828182845904523536
This seems to make the Excel formula work like a champ! Maybe this will come in handy for someone, someday...but probably not!
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a10t2
Official Poobah of No Life.
Posts: 4401
Ask me why I don't like Chico!
Re: Tinseth Hop Calculation Help
«
Reply #3 on:
January 16, 2010, 08:28:37 PM »
You can also enter it exactly (or at least, to a whole lotta digits  I don't know if Excel uses a stored value or not) by using the exp() function.
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Sent from my Microsoft Bob
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hopfenundmalz
Global Moderator
I must live here
Posts: 8817
Milford, MI
Re: Tinseth Hop Calculation Help
«
Reply #4 on:
January 19, 2010, 12:33:42 AM »
Remember that your input data will be 2 sig. figures.
Don't quote your output IBU's to 12 decimal places.
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Jeff Rankert
Ann Arbor Brewers Guild
AHA Governing Committee
BJCP National
Homebrewing, not just a hobby, it is a lifestyle!
skiwithg
1st Kit
Posts: 8
Re: Tinseth Hop Calculation Help
«
Reply #5 on:
January 19, 2010, 11:47:58 AM »
FYI  Tinseth was on a recent episode of Brew Strong podcast.
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