Terrible Efficiency, how to fix low gravity
 

I was making an attempt at my first wheat beer today. I'm not sure what happened but I only got about 45% efficiency and am now stuck with a beer with an OG of 1.028...

I have a couple pounds of gold DME... can I boil some to and add to raise the gravity? How much will this affect the final taste.

Is it too late for my beer?

...And Yeast is already pitched so I can't add DME and re-boil....

Sure; you can add the dme. Just make sure you include the water you'll be adding too when you do your calculations.

If you did a partial boil and topped off with water.That is your answer to a false reading.Do you know what you did to get such a low gravity? I would start with this before adding more.

It was a full boil... I think it was a combination of factors: First time using wheat, didn't get a good crush. And not an aggressive enough boil... I think I ended up with somewhere around 6+ gallons instead of the 5.5 that I had planned on.

you could have kept boiling down to 5 gallons.

Curious....
 

Where did you get your grain? I too, brewed a wheat today. I've done many of them, but today, the efficiency was about half of my norm....

Be interesting if we both got our grain from the same place.... looking back on what I did today, I have a suspicion or two about the grain I received from my usual supplier.

Hindsight is 20-20.

I could tell I was a bit over, but not that much

I got mine from my LHBS... Apparently it's not uncommon to get a bad crush when using wheat though

Your efficiency might not actually be that bad (at least better than 45%). I see people on this forum tricking themselves usually into a better efficiency value, but sometimes into a worse one. Both are down with the same mistake: using the expected efficiency for a 5g or 5.25g batch but got either far more or far less wort.

What was you expected OG at 75% efficiency? If you were expecting an OG of 1.047 for 5.5 gallons, then you actually got a 65% efficiency.

If you had 6 gallons of 1.028 then you would have 5.5 gallons of 1.031 if you had boiled it down.

And yeah, adding some DME to up the OG would be a good idea. Watch your water volumes more importantly next time!