measuring efficiencies

[timbo41]

Never really worried about efficiency too much but thought I'd try it out next time as an academic exercise. I mainly single vessel brew now, fill up the burco to about twenty litres then add grainbill ...nomally around 4 kg don't go high grav. Mash, mash out then do a five litre or so simple sparge of bag. Not sure when to take pre boil sg ....when starting the boil, at boil,when the bag runnings are added as evaporation occurs.

[timbo41]

(Continues) sorry phone being a pig!!
So any advice appreciated.

[sbond10]

I've not biab yet but from the things I've been reading its as soon as you pull the grain out of the pot measure your gravity then and the temp so you can get alter the figure on your hydrometer.

As I said I'm currently pulling everything to biab so until a more experienced member comes along and corrects me I think I'm right

[Twistedfinger]

Never really worried about efficiency too much but thought I'd try it out next time as an academic exercise. I mainly single vessel brew now, fill up the burco to about twenty litres then add grainbill ...nomally around 4 kg don't go high grav. Mash, mash out then do a five litre or so simple sparge of bag. Not sure when to take pre boil sg ....when starting the boil, at boil,when the bag runnings are added as evaporation occurs.

I usually/used take a sample after pulling the bag and adding the first of the runnings, as I use a refracto these days it now just a few drops. I cover the top of the jar with tin foil and pop it in the fridge. I add the squeezed runnings as and when I've finished squeezing,it won't alter the gravity just gives you more wort. When the sample is cool enough I take a reading and throw it back into the pot.

[killer]

Well,

For a pre-boil gravity, it should really be after sparging when you have your maximum volume. Obviously measuring post-boil is important in getting your OG. Don't forget this won't actually change your efficiency, you'll just have a lower volume of higher gravity wort. For me, measuring pre-boil gravity is just about making sure you haven't messed up somehow and have gotten most of the sugars and don't need to sparge any more.

I once measured my gravity after pulling the bag, and then sparged 6L separately and measured that gravity - it was useful to find out how much I might be losing if I didn't sparge - quite a bit actually I had 10% of all the theretical sugars in the whole grain bill, although I am maxi-BIABing.