1st running gravity vs pre boil gravity vs post boil gravity

How should the gravity readings compare:

a) 1st running of batch sparge gravity
b) 2nd running of batch sparge graity
c) pre boil gravity
d) post boil gravity

Should the 1st running be equal to, higher, or lower than post boil gravity (starting gravity)?

I think my first running is too far below my intended starting gravity, then by adding the 2nd running, I am way below and then have to boil off more than I should have to (2 hour boils).

thanks in advance

Your first running should be the highest. The second running should dilute you down to close to your pre-boil. Boiling will concentrate the wort and should give you your post boil at the predicted post boil volume.

Compare your 1st running gravity to table 1 here:Braukaiser. This will tell you how well you are converting in your mash. You should be able to achieve percentages in the 90's.

Is your total collected wort significantly lower than predicted, or do you know what it "should" be prior to starting?
Cant say I've ever measured first runnings, only second runnings to make sure I didn't take it too low. Can you post one of the recipe's you had problems with and your actual gravity readings?

Thanks. Ill go through that info on BKs site tom, hopefully will clear some things up.

Yes, total pre boil gravity is low so I have to boil off a lot to get to my intended starting gravity. I'm guessing my first running should be around by intended gravity, then diluted by second running, then boil brings it back up.

Ill post recipe and gravity readings from notes tom.

Thanks.