Efficiency - PreCrushed Grains/Flaked Oats

[sicktght311]

So two parts to this

1) Does anyone else always find their efficiency of a recipe that uses flaked oats, ends up lower than expected by a few gravity points (3-5 on average)? Assuming a recipe is fairly straight forward with 12lbs base grain, 3lbs flaked oats, i find i'm always off compared to my recipes for something like a Blonde ale with no flaked or adjuncts.

2) I've been brewing a similar recipe as number 1 for years, so i recently brewed it again yesterday. Due to an error in packaging, i got sent a bunch of bags of Pre-Crushed pilsner malt from More Beer by accident instead of uncrushed since i run my own mill with my own crush (morebeer did make it good, and sent me the correct uncrushed grains, and let me keep the crushed bags). I dumped the crushed malt in directly from the bags just so i could start to use em up and get rid of them, and at the end of my brew day my efficiency was AWFUL. The recipe was 10lbs of Pils, 3lbs Flaked Oats, and 1lb Carapils, with an expected OG somewhere around 1.062 according to my calculations, but i ended up at 1.050. Way off. Is it just a combination of Flaked Oats, and poor crush from the precrushed morebeer stuff?

I know the easy way to test is to just re-brew this recipe with my own crush, but i also have another 30 or so lbs of this crushed grains so if i need to use it again in the future, i'll want to try to account for it.

 

[balrog]

You can always run their-crushed through your mill before using it.
I get 8-10% less efficiency when using lots of wheat, but not noticed the recipe SG modelling is way off when I put flaked oats in something like an oatmeal stout.

 

[sicktght311]

You can always run their-crushed through your mill before using it.
I get 8-10% less efficiency when using lots of wheat, but not noticed the recipe SG modelling is way off when I put flaked oats in something like an oatmeal stout.

Yeah i thought about running it through my mill again to double crush, but also dont wanna deal with a stuck sparge if it gets too fine. Might try this next time and see if theres any change.

 

[doug293cz]

Are you fly sparging or batch sparging? If batch sparging, the flaked adjuncts could increase your grain absorption rate, which will lower your lauter efficiency somewhat from normal. Grain absorption rate is easy to calculate from strike water volume, first runnings volume, and grain bill weight using the following formula:

Absorption rate = (Strike water volume - First runnings volume) / Grain Weight​

​

For best accuracy, both volumes should be corrected for expansion to room temp.

The bad efficiency using the store crush is probably mostly due to crush. Coarse crushes take longer to convert than finer crushes, and can result in low conversion efficiency if the mash is not long enough to get close to 100% conversion.

Brew on

 

[day_trippr]

I think pretty much everything above is crush related. I mill oats and wheat separately (0.025" gap vs 0.032" for malted barley) because I did notice running those malts with the barley dropped the overall extract efficiency by a handful of points. No bueno.

But I never noticed a similar loss of extract using flaked wheat or oats - always hit the BS3 prediction. I do not run flaked grains through my mills as I condition the barley and don't want to load up my rollers with oat or wheat paste

Cheers!