StefanR Posted February 18, 2012 Share Posted February 18, 2012 I would like to work out the finished IBU of an APA kit brewed to 23L. Your website quotes an IBU of 340 for the APA kit, but what does this work out to, after diluting and mixing to 23L of wort? Cheers Stefan Link to comment Share on other sites More sharing options...
Hairy Posted February 18, 2012 Share Posted February 18, 2012 You multiply the tin IBU by the size of the tin and divide it by the volume. In your case: 340 x 1.7 / 23 = 25 IBU But there is a loss during fermentation of around 10-20%. So the final IBU may be around 22. Link to comment Share on other sites More sharing options...
StefanR Posted February 20, 2012 Author Share Posted February 20, 2012 Cheers for that [biggrin] Link to comment Share on other sites More sharing options...
AdamH1525226084 Posted February 22, 2012 Share Posted February 22, 2012 Hmmmmm, I wish I had read the FAQ section on this before I used the "Kit and Extract Beer Designer" spreadsheet. That uses the following formula: Kit IBU * 1.25/ volume. So, an IPA I did according to the spreadsheet would have an IBU of 44.3. But the Coopers formula equates to 60.3. [pinched] Oh well, I love bitter anyway [w00t] Link to comment Share on other sites More sharing options...
***** Posted February 22, 2012 Share Posted February 22, 2012 Hmmmmm, I wish I had read the FAQ section on this before I used the "Kit and Extract Beer Designer" spreadsheet. That uses the following formula: Kit IBU * 1.25/ volume. So, an IPA I did according to the spreadsheet would have an IBU of 44.3. But the Coopers formula equates to 60.3. [pinched] Oh well, I love bitter anyway [w00t] Good to see that you are looking into the calculations that this spreadsheet makes Adam. You prompted me to go and have a look, and I was tempted to change the formula. However when checking the FAQ I see, as Hairy points out, fermentation losses of up to 30%. Ian Haworth is obviously allowing for about 26.5% loss in bitterness. I guess it's just a matter of which way you want to account for these losses, the main thing is that you do it the same way for every Brew so that you have a valid reference point. Link to comment Share on other sites More sharing options...
AdamH1525226084 Posted February 22, 2012 Share Posted February 22, 2012 Hey Scott. I found a post somewhere that was related to it - the kits are 1.25 L apparently, but Coopers use the weight, not the volume, "* We use the weight because our quoted colour/bitterness figures are based on a 10% weight/volume dilution." So, I have replaced the 1.25 with 1.7 in my copy of the spreadsheet. The FAQ says "Generally, fermentation reduces colour and bitterness by between 10 to 30%." 10 to 30% can be quite a difference - for IBU of 60.3 in my IPA brew that can then vary from 42.2 - 54.3 [pouty] Link to comment Share on other sites More sharing options...
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