How much DME to bring up OG of an all grain

I have my brew in the kettle and the OG of my all grain batch is 1.050. It needs to be 1.068. How much DME do I add to get it up to my OG? Thanks

Is the boil done yet? If not, the wort will concentrate a bit more and your gravity will rise some more. Also, how big is the batch? 5 gal? 5.5 gal? 10 gal?

Also, you might want to get brewing software because it will calculate these sorts of things for you. There are even some decent freeware ones out there. A good one is Qbrew, if you are interested (http://www.usermode.org/code.html).

The extract potential of DME is about 1.045. This is important because you'll use the gravity units of that (45 - just subtract 1 and * 1000).

For example sake I'll assume you're aiming for a 5 gallon batch and you're run-off after mashing (before boiling) is 6.00 gallons. To hit your gravity you need to apply the following formula :

((GU of Desire OG * Desired Batch Size) - (GU of wort))/ GU of DME

So, for this example you get :

(68 * 5) - (50 * 6)) / 45 = .89lbs of DME

Thanks to John Palmer's "How to Brew."

I've used this and can typically hit my OG within 1-3 units.

Hope this helps.