Option to show calculations

[matty0ung]

          Good morning programmers,

Just a thought from a user trying to understand a bit more without the
desire or skills to dive into programming.

Would it be possible to build in a way to check and/or ajust formula's
according to ones own experience? I don't like the idea that I can not
see the calculations behind the outcome.
I know my input and I see the output but what's going on in the black
box?

Thanx

Rob

Originally posted by @ID2GO in #715 (comment)

[matty0ung]

Hello,

I haven't looked at this in detail, but I imagine it would be possible in most cases to show the calculations, albeit with a couple of caveats:

• Internally, the code does everything in metric units (kilograms, liters, degrees Celsius, etc). So, for anyone using US Customary or Imperial units, the calculations might be a bit harder to follow.
• In a small number of places, we use "look-up tables", where the explanation would have to be something along the lines of "from amount X, we look up the closest corresponding amount Y from a standard look-up table". Eg, all the data in https://github.com/Brewtarget/brewtarget/blob/develop/src/measurement/SucroseConversion.cpp was compiled from actual measurements by folks at the US Department of Agriculture back in 1936!
• From memory there are a few cases where we have a formula for how to get x from y and we then use some numerical methods (eg divide and conquer) to do the reverse (get y from x) because the actual formula to get y from x would be more painful to use. This all works fine, but we'd have to think about how to show what's going on!

However, if you wanted to be able to arbitrarily adjust any formula in the program, that would be a somewhat taller order (and, in all honesty, not something I imagine many people would want). There are already a fair few parameters you can modify, and, in some cases, you have a choice of algorithms -- eg you can choose between Tinseth, Garetz, and Rager methods for estimating how hop additions affect bitterness levels in the wort at the end of the boil. So, it might, more realistically, be a question of finding out which existing parameters you need to tweak or whether there are any others that could usefully be added.

[matty0ung]

I think being able to show our calculations is definitely a good idea by the way. For one thing, it would help ensure we are doing things correctly.

[ID2GO]

Hi Matt, Thanx for your quick reply! One thing that makes me wonder is that my calculations with Brewtarget differ sometimes from those made by bigger breweries where I brew my beers. I'd like to be able to look "under water" and compare & if need be, ajust, the formula's used by either them or me. Sometimes the SG calculations differ. It is good to have an expected FG outcome calculated by the specs of the yeast but sometimes, as in many areas of life, reality surpasses or fall short of expectations. Therefore, if possible, I'd like to be able to have an option to put in a manual FG. That the software can also take into account. One of the things I've stumbled upon is that I'd like to understand & play with the calculation of the IBU. The ketle I use is insulated and keeps the boiling heat (100°C) for well over an hour after flame out. This means that it continues to contribute some to the bitterness, even after flame out. But this is not something that I can toggle on or off. Here a few of my thoughts. I realize that a fool can ask many more questions than the wise can answer.🫣 Rob Op wo 19 jul. 2023 08:36 schreef Matt Young ***@***.***>:

…

I think being able to show our calculations is definitely a good idea by the way. For one thing, it would help ensure we are doing things correctly. — Reply to this email directly, view it on GitHub <#763 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AIF3BIVUDNJIQXTXT6SR2OLXQ557XANCNFSM6AAAAAA2OWRRJA> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[matty0ung]

Please keep asking questions! I'm still learning bits of the software myself, so I definitely don't know all the answers, but one way or another we can get to the solution.

I don't know if you already know about this feature, but you can put in actual figures for OG, FG and so-on in BrewNotes (select a recipe and click the right-most icon on the top row). But, yes, if you want to systematically tweak the formulas, that would be a new feature.

I'm still deep down a rabbit hole on BeerJSON at the moment. But when that's finally finished, I want to come back and look at all the formulas etc -- for this and for #728. It's in the nature of things that a lot of the calculations are estimates or approximations, but my ambition is that we should be as clear and as accurate as possible with them -- including allowing you to take account of factors such as insulated kettles etc.