36 replies to this topic

[stellarbrew]

Tinsith definitely looks more like a function I would expect to see for utilization. The nerd in me wants to change my spreadsheet now! Where can I find a definition of the function?

I got the formula from Palmer's book for my spreadsheet. It is as follows:function of boiling gravity, f(G) = 1.65 x 0.000125^(Gb-1) , where Gb is boiling gravity (such as 1.047)function of time, f(T) = [1-e^(-0.04 x T)]/4.15 , where T is hop addition boiling time in minutesUtilization = f(G) x f(T)

[chuck_d]

The one thing about those plots that you also don't notice is the affects of gravity. Rager doesn't take gravity into account at all until 1.050, all the formulas are in the link I gave above in post #7.

Edited by chuck_d, 10 April 2009 - 09:23 AM.

[MtnBrewer]

Maybe I'll just stick with Tinseth after all, and shoot for lower bitterness instead. Rager looks most bogus of all, and Garetz is flawed from the get-go because of course you get SOME bitterness if boiling less than 10 minutes. Tinseth all the way, baby. Thanks for the info. It confirms what I thought I knew for many years.

I'm not so sure about that. I've heard it postulated that there is no isomerification in the first 10-15 minutes. So there may some jusification for that.

[ThroatwobblerMangrove]

I'm not so sure about that. I've heard it postulated that there is no isomerification in the first 10-15 minutes. So there may some jusification for that.

An interesting point...

[stellarbrew]

The one thing about those plots that you also don't notice is the affects of gravity. Rager doesn't take gravity into account at all until 1.050, all the formulas are in the link I gave above in post #7.

That would be because utilization is a function of both gravity and time. For a two-dimensional plot, you could choose utilization versus time, or utilization versus gravity, but not both. To plot for both parameters, you would need to do a 3-d plot.

[chuck_d]

That would be because utilization is a function of both gravity and time. For a two-dimensional plot, you could choose utilization versus time, or utilization versus gravity, but not both. To plot for both parameters, you would need to do a 3-d plot.

Yeah, I just wanted to point out the way Rager was handling that, by ignoring it for smaller beers altogether while Tinseth has a "Bigness Factor" that takes gravity into account for all batches.

[stellarbrew]

Yeah, I just wanted to point out the way Rager was handling that, by ignoring it for smaller beers altogether while Tinseth has a "Bigness Factor" that takes gravity into account for all batches.

Duh, I gotcha now. I had read your post as two sentences, two separate thoughts for some reason.

[robert41]

not sure what the function is , check this out https://www.realbeer...s/bcalc_js.html

[djinkc]

Yup, Jackie Rager is a local around our parts huh!

Yeah, he's a wealth of knowlege around here. But the formulas are only worth what you put into them though. I think at the homebrew level it really doesn't make that much difference since we have so many other variables. But we have a great place to start. Jackie (Rager) gave a very informed presentation about a year ago at one of our local mtgs on how he arrived at his way of calculating HBU. Unfortunately I was in my talking (read - Swagman was there) mode and was asked to STFU a couple times . Great info, but I don't remember anything.. I had heard it before...............

[chuck_d]

not sure what the function is , check this out https://www.realbeer...s/bcalc_js.html

That's Tinseth, from his webpage: https://www.realbeer.com/hops/Formula for utilization in the page is:util[i] = 1.65*Math.pow(0.000125, gravity)*(1-Math.exp(-0.04*time[i]))/4.15;

[robert41]

That's Tinseth, from his webpage: https://www.realbeer.com/hops/Formula for utilization in the page is:util[i] = 1.65*Math.pow(0.000125, gravity)*(1-Math.exp(-0.04*time[i]))/4.15;

Chuck, have a question about the formula format, i probably could understand the formula but i never seen one like this. i am confused as to exactly how Math.pow, Math.exp, and the "," in (0.000125, gravity) fit into the whole oder of operations. Is there a simple way to write it out like in math class, lol

[MtnBrewer]

Chuck, have a question about the formula format, i probably could understand the formula but i never seen one like this. i am confused as to exactly how Math.pow, Math.exp, and the "," in (0.000125, gravity) fit into the whole oder of operations. Is there a simple way to write it out like in math class, lol

pow(x,y) is the same as x^yexp(x) is the same as e^x

[chuck_d]

Chuck, have a question about the formula format, i probably could understand the formula but i never seen one like this. i am confused as to exactly how Math.pow, Math.exp, and the "," in (0.000125, gravity) fit into the whole oder of operations. Is there a simple way to write it out like in math class, lol

Heh, yeah, I just copy & pasted his formula from that page, which is written in Javascript.Check this out and let me know if you have any questions, it shows both Rager & Tinseth formulas:https://dieseldrafts...mulas.html#hops

[stellarbrew]

I have a question for chuck_d, or anyone who may be able to offer insight. I notice from chuck's attachment early in this thread that Tinseth is formulated for whole hops loose in the boil. I have noticed that I get a higher utilization when using pellets than with whole hops. Is there a generally accepted or commonly used correction factor that can be applied when using pellets? Intuitively, I feel like the difference may be on the order of 10% more utilization with pellets, but I'm not sure whether it would be constant percentage correction throughout the range of times and gravities, or whether 10% is even really accurate for that matter. Does anyone know?

Edited by stellarbrew, 13 April 2009 - 11:52 AM.

[MtnBrewer]

I have a question for chuck_d, or anyone who may be able to offer insight. I notice from chuck's attachment early in this thread that Tinseth is formulated for whole hops loose in the boil. I have noticed that I get a higher utilization when using pellets than with whole hops. Is there a generally accepted or commonly used correction factor that can be applied when using pellets? Intuitively, I feel like the difference may be on the order of 10% more utilization with pellets, but I'm not sure whether it would be constant percentage correction throughout the range of times and gravities, or whether 10% is even really accurate for that matter. Does anyone know?

I don't know that the raw data are there to back this up but I've heard the number 10% tossed out there. That's the default value in ProMash. I've played around with it in ProMash and the Tinseth model appears to give a bigger boost to utilization from pellets for shorter boil times. Whole vs. pellet is pretty close for boil times of 60 minutes or more.

[stellarbrew]

I don't know that the raw data are there to back this up but I've heard the number 10% tossed out there. That's the default value in ProMash. I've played around with it in ProMash and the Tinseth model appears to give a bigger boost to utilization from pellets for shorter boil times. Whole vs. pellet is pretty close for boil times of 60 minutes or more.

If you've heard 10% mentioned before, and it's the default inProMash, that supports my own subjective assessment, and definitely gives me more confidence in using that number. That also make sense that as the boil goes longer the differences would be less. Sans any further info, I'll have to think about what kind of curve to apply to the correction factor.Thanks for the info.