# My Gift to all Homebrewers: I created a fast and accurate brewing calc



## kaisenberg (15/2/17)

Hi all, I'm a long time lurker here on AHB and I have recently made a homebrewing tools site to help out the homebrewing community. I recently posted it on the Homebrewing subreddit (https://www.reddit.com/r/Homebrewing/comments/5twsi5/my_gift_to_all_homebrewers_i_created_a_fast_and/) where I got a lot of postive feedback and I thought you guys/girls might appreciate it. 

The site is http://thebrewlist.com/. Please tell me what you think and if you have any suggestions please let me know here. If this is the wrong section for it or I haven't posted enough times could the mods please delete this or move it the proper section.

Cheers,
James


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## Liam_snorkel (15/2/17)

looks good. The "alcohol content" link appears to be blank though.


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## sp0rk (15/2/17)

Very glad to see your calculator will do hydrometer temp corrections above 70c, the brewer's friend one doesn't and it shits me to tears when I'm trying to judge efficiency while I'm cubing (which I know isn't super accurate)


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## Meddo (15/2/17)

Well done James, looks simple and handy.

My recommendation (request?) would be to list the equations used to perform each calculation, whether on the relevant calculator page or in a reference page elsewhere, and include a source for that equation where appropriate. I've found some different equations in use for some calculations (e.g. ABV, Plato to SG, etc.) on different sites, and also some calculators or brew builders that give inaccurate results. Having the actual equations used available for review somewhere allows people to validate that the calculator is working as intended rather than having to trust a black box.

Because of the issue above I've built my own calculators for personal use but they're spreadsheet based - I'd much prefer to use a web page for the accessibility advantages if I'm able to confirm that the calculators are working as intended.

BTW this request isn't specific to your page, very few of the web calculators seem to make their equations visible to users. Maybe I'm the only one concerned by this? Oh well, maybe I should just RDWHAHB etc. 

Edit: I just noticed that you have included a link to some formulae used (e.g. diastatic power) - nice one.


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## kaisenberg (15/2/17)

Thanks Liam, the alcohol content calculator should not be blank anymore.

Hey Meddo, I'm glad you like it! I understand it is pretty confusing without the formula especially when sites have alternative/standard equations. To make it more trustworthy I have added some references to the converters and I will put more references and equations below the calculators in the following days


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## moonhead (15/2/17)

Whats the source for those carbonation styles? Them seem too low. 1.9 vols for and IPA seems very low (for example).


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## Lyrebird_Cycles (15/2/17)

The gravity conversion calculator appears to use formulae that result in a serious discrepancy between oBx and oP, where the difference should be very small.

As an example, entering 1.004 SG your calculator gives oP ~= 11.9 and oBx ~= 12.4, a difference of about 0.5 where the difference should be about 0.002 (difference is given approximately by -52.6942 + 151.6394 * S - 145.4101 * S2 + 46.4631 * S3)


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## mtb (15/2/17)

The pedant in me wants to point out that the Sugar Priming / Kegging calculator refers to fermented & uncarbonated beer as wort. At that stage it's beer, not wort


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## kaisenberg (15/2/17)

The PSI for the keg is calculated using the formula in this email http://hbd.org/hbd/archive/2788.html#2788-8. I have also changed it to say Beer instead of Wort which is a fair point by mtb.

Hey lyrebird I will look more into the conversions of Plato to Brix but it might be due to not enough decimal places to make it accurate. If you have any good sources for this that might also be helpful.


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## moonhead (15/2/17)

I think the forced carb calculation is correct, but the style guidelines seem off.


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## Drowro (15/2/17)

James - Looks good mate. Simple, easy to read. Well done!


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## Lyrebird_Cycles (15/2/17)

Standard formulae are on the appropriate wikipedia page.

°Bx = 182.4601 * S3 - 775.6821 * S2 + 1262.7794 * S - 669.5622

°P = 135.997 * S3 - 630.272 * S2 + 1111.14 * S - 616.868 .


There's not really any point in using both scales, to the degree of accuracy possible with standard equipment they are identical.


Please note there's a typo in my post above, the conversions are from 1.040 not 1.004.


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## mr_wibble (18/2/17)

The AbV calculation differs from Beersmith Mobile

1.048 -> 1.010 => 5.0% AbV (Beersmith)
1.048 -> 1.010 => 6.2% AbV (thebrewlist.com)


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## moonhead (18/2/17)

Mr Wibble said:


> The AbV calculation differs from Beersmith Mobile
> 
> 1.048 -> 1.010 => 5.0% AbV (Beersmith)
> 1.048 -> 1.010 => 6.2% AbV (thebrewlist.com)


It's showing 5.06% ABV for me on thebrewlist.com.


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