Correct Calculations ?

[pas8280]

Just wondering if anyone can help me with this conundrum I am planning a Moorhouse's Pendle Witches Brew from Graham's book in the morning, and as it is only a 17L brew length i put the recipe into a grain recalculator to amend the bill from stated 23L length to 17L length.
With the results i put them into beer engine this gave me a different OG from the book, 0006 to be exact so this will give me an appropriatly higher strength beer than stated 5.2% ABV.
So my quandary is do i scale down the whole of the grain bill in beer engine to suit the book or have i missed something obvious
Quick update just put the 23L grain bill into beer engine and it gives the same result as the 17L which is way different to the book im confused (doesnt take much ) HELP !
Cheers Paul

[Manx Guy]

Hi,

Follow these steps:

Enter the recipe into Beer Engine as it appears in the recipe (for 23l brewlength)

Once you have entered the recipe ensure that both the gravity and IBU 'fixed' check boxes are ticked...

Then (and only then) change your brewlength...

voila! your grain bill has been adjusted to the right amount!


Happy days!



Guy

[pas8280]

Thats just the problem Manx Guy even when entering the grain bill exactly as the book with the same brew lengthof 23L, it gives a higher OG than the book ??

[boingy]

What is your efficiency set to in the software? I think the book is based on about 70%.

[pas8280]

Ah that will be it Boingy i knew i would be missing something obvious thanks (feel silly now der)

[StrangeBrew]

If you go to 'About the Recipes' on page 84 there is a simple formula for converting from one brew length to another.

To convert from one volume to another divide the required brew length by the recipe brew length to get a figure then multiply all ingredients by that figure.

Example:
17 / 23 = 0.74
0.74 x all ingredients including hops.