No-Sparge Efficiency Problems with flaked oats/barley??

[shotputman]

Trying to figure out potential issues here. I've recently started trying no-sparge in my 15gal Blichmann Boilermaker. First two batches efficiency was around 65-70% (which is about what I hit when I batch sparge). My last two batches have been 50% and today 48%!

Only thing I can think of is that the last two grain bills have had flaked grains. One was about 20% flaked oats/barley and the other was 7% flaked oats/barley. The previous batches had no flaked anything.

Could the flaked ingredients be causing a huge efficiency drop? If not, I'm totally stumped as to what could have changed.

 

[JohnSand]

I've experienced flaked grains holding more liquid, so lower volume.

 

[eric19312]

At 7% I don’t see it. The flaked grains don’t bring any enzymes to the mash so are going to rely on the enzymes from your malted grains. But most malted grains have way more than enough enzymes to share with even your 20% flaked addition.

Possibly it is dough balling differently than you are used to. Might need to stir it better or a few more times during mash.

Also with no sparge brewing I think you should be checking gravity of your mash and keep mashing until you reach your target pre boil gravity. A refractometer makes this easy to do. No real reason to miss target by that much if you have flexibility to extend your mash a few minutes.

 

[Smellyglove]

What was the expected or actual preboil SG for all these beers? A bigger grist will give you lower efficiency.

 

[doug293cz]

If you provide the following pieces of data, I can do a pretty complete analysis of your conversion and lauter efficiencies (which when multiplied together give you your mash efficiency.) The analysis is only going to be as accurate as your most inaccurate measurement.

Data Required:

Grain bill total weight:
Strike water volume:
Pre-boil volume:
Pre-boil SG:​

Brew on