First AGB...missed my target SG...need ideas

[hog2up]

did my first AGB today. hit my mash temp of 154F and held for 60 minutes at that temp.

fly sparged my 4.5 gallons at 170F...drawing 1/2 quart per minute. got a little over 7 gallons of wort from 9.08 gallons of mash and sparge. water.

supposed to hit 1.042-44 preboil SG.....hit 1.34. had to add some malt extract to bring it up to 1.044 before boil.

thinking my grain crush for the wheat wasnt fine enough...looking for thoughts as to why i missed so my preboil SG by so much.

dunkle weizen:

Ingredients
Amt Name Type # %/IBU
8.0 oz Rice Hulls (0.0 SRM) Adjunct 1 4.3 %
6 lbs Red Wheat Malt (2.4 SRM) Grain 2 52.2 %
2 lbs Caramunich Malt (60.0 SRM) Grain 3 17.4 %
1 lbs Barley, Raw (2.0 SRM) Grain 4 8.7 %
1 lbs Cara-Pils/Dextrine (1.5 SRM) Grain 5 8.7 %
1 lbs Wheat Malt, Dark (9.0 SRM) Grain 6 8.7 %
1.00 oz Tettnang [4.80 %] - Boil 30.0 min Hop 7 13.3 IBUs
1.0 pkg Hefeweizen Ale (White Labs #WLP300) [35.49 ml] Yeast 8 -

 

[iambeer]

Maybe your sample wasn't representative of the wort? How did you extract the sample?

Did you take a sample after boil?

 

[zzARzz]

I took a preboil gravity reading once that equated to about 30% efficiency, but then I realized I drew off the top of the wort before mixing. I stirred it really well, measured again and found my gravity numbers were dead on.