first all grain brew

I did my first all grain this last weekend and everything went fairly smoothly. I did come up short on my gravity a bit. I didn't take the reading until after the boil. If you check it before the boil will it be the same?

I have some dme on hand and was going to add that, but since I didn't know about it till after the boil I just let it go. It wasn't too low. My question is What is the procedure for checking gravity and adding some extract if you want to compensate?

Can anyone give a short answer to how you check efficiency?

Thanks

IMO the best time to check gravity is right after runoff and before boiling. You only have to deal with the deadspace in the lautertun in terms of losses. Post-boil the gravity will obviously be different (higher), but the volume will be lower, as well, so the calculations will yield the same efficiency whether you check pre or post-boil.

However...as you note, the time to make adjustments to your gravity if you miss it to the low side is pre-boil. If you check pre-boil you can shore up your gravity with a bit of DME.

Yup, what Barron siad.
I am a stats geek, so I take samples at very beginning of run-off, somewhere in the middle and again near the end, Then I take grav reading of the aggregate pre-boil.
The Imperial stout I made had a gravity of 1.095 on the first runnings, and was still at about 1.04 after getting over 9 gallons out of the mash.

Baron von BeeGee said:

IMO the best time to check gravity is right after runoff and before boiling. You only have to deal with the deadspace in the lautertun in terms of losses. Post-boil the gravity will obviously be different (higher), but the volume will be lower, as well, so the calculations will yield the same efficiency whether you check pre or post-boil

Click to expand...

You would think so. One day I decided to check my pre boil gravity @ 7.25 gallons(not something I normally do) to judge my expected final gravity and came up way short. I was racking my brain during the rest of the brew session how this happened. When the boil ended @ 6 gallons and I had time to check the gravity, to my surprise I still hit my gravity. This isn't rocket science, 6 divided by 7.25 is 82.75%. My pre boil gravity was no where near 82% of my post boil. I started coming up with this theory that gravity follows a non linear path. Who am I kidding, thats sober talk and just need to find out where I screwed up. That will be my mission on the next batch.

Also remember that no matter what your efficiency is, the OG of the wort in the fermenter is the most important aspect. If you are making a recipe with a gravity of 1.054, over or under shooting it will not make the beer you set out to make.