Just finished brewing my second witbier in a row. Both had the following grains with an 80% eff.:
1.051 OG -

4.5# flaked wheat
4.25# belgian pilsner
1# flaked oats
2 oz melanoiden

I performed a single mash infusion at 154 deg F/60 min. Both brewdays went well except for one catch. After the boil and chilling I hit an OG of 1.042!! My kettle levels were spot on and hydrometer calculations were adjusted for within the temp range.

I have brewed this recipe several times before and ALWAYS used a 122F protein rest and have had no problems in the past hitting my desired OG. Herein lies my question:

Could the lack of a protein rest have accounted for such a low OG being missed by so many points? It doesn't seem like it could or should, but I just wonder if some of the sugars in the flaked oats/wheat couldn't be reached due to beta-glucans and other proteins locking them in? I have used pre-gelatinized flaked wheat and oats plenty of times before with no issues or lack of gravity points, but in a beer like this that uses 50% + may have needed a protein rest to allow the enzymes full access to starches for conversion. The flaked grains were NOT ground but rather added directly to the mash tun if that helps people figure things out. I did add back 1# of wheat DME to make up for lost points.

Any ideas or suggestions to help me solve this quandry. I will now go back to doing a protein rest for this style to make sure my numbers are on. I guess I wanted to see if I could make a wit w/o a protein rest to save some time. Shame on me!

Was everything else exactly the same for the 2 batches? Same bags of grain, same crush?

I crushed the flaked grains with my pilsner malt the first time and hit my low OG. I then thought that maybe the pilsner malt didn't get crushed well enough due to the flaked grains getting in the "way". So for the second batch I crushed the pils malt first, then added the uncrushed flaked grains to the mash with the crushed pilsner malt. Still quite a low OG.

I know my crush is fine b/c the week before I used my mill for a double IPA at 1.080 OG and nailed it. It simply doesnt make sense to me. Obviously if doing a protein rest helped gain ppg then more people would be doing short ones to help boost their efficiencies. Still a mystery to me.