Understanding sugar kettle additions and efficiency calculations

[Brewer #88351]

Hi,

I am trying to understand why my efficiency looks so high. One suggestion put forward is that the addition of brewers sugar directly into the kettle has an affect the the efficiency calculations.

Is this true and if so can I do anything to remedy my calculations?

Thanks,
JT

Link to full thread:
http://www.thehomebrewforum.co.uk/showthread.php?t=69128

 

[J A]

Assuming that you took pre-boil gravity without the sugar addition, your mash efficiency is 99%. That seems high and there may be something off there, but your pre-boil efficiency reflects the wort gravity with no sugar addition. You should have taken a post-boil gravity before you added sugar (often added at flameout or late in the boil). that would have been your true kettle efficiency. Since you added sugar in between the 2 readings that you do have, the efficiency appeared to go up. If you'd taken a reading after boil but before sugar addition, you could have added less or no sugar and hit your desired OG.

 

[GFHomebrew]

All I can see is that you have your boil off rate for a 60 minute boil at over 5lt but your actual boil off was 3lt. My batches have similar water requirements to you. My pre boil volume is usually 28lt and into fermenter 21lt with about 1 lt kettle dead space that gives me 6lt boil off for 90 min boil. I see for your 60 min your boil off was 3lt but your final gravity rose 10 points as well that is a miss calculation I think? I get roughly 10points of gravity out of a 90minute boil with 6 litres of boil off yet you get the same amount with 3 lt boil off mmm?

80g of Dex I think can't throw your final gravity by to much it's only 80g. Anywho looks like you've got some dealing in to do.

Your getting some pretty awesome extraction too what was your strike volume? What was your sparge volume?