Improving efficiency when using wheat and oats

[tubbsy]

I did 2 back-to-back brews on Saturday with identical mash schedules, but got very different efficiencies.

NEIPA = 72% conversion, 65% brew house
Best Bitter = 92% conversion, 82% brew house

The obvious difference is the NEIPA had 13% malted wheat and 13% rolled oats. What can I do to help the conversion when using wheat and oats?

 

[MHB]

One of the obvious things to look at is your crush. Wheat is a smaller harder grain than is Barley, when I'm using a largish wheat fraction cracking the wheat separately and maybe a couple of times until it’s a fine kibble helps a lot. Just tossing it through with the Barley malt tends to give very large Wheat fragments that are harder to get the extract out of, or very fine flour that blocks up the lauter/sparge, (depending on your crush) both knock the snot out of efficiency.

The other is that you really need to mash differently when you have a lot of unmalted adjunct. Mash in around 40oC, raise to slowly to around 50oC to give Glucanase and Protease a chance to make the starch granules available to the Amylase at your normal mash temperatures. Remember that Oat Starch doesn't gelatinise until 52-66oC (gelatinise means take up water, swell and be open to amylase attack) but before that can happen it needs to be dug out of the matrix of glucan and protein. Sure that is meant to happen during flaking but flaking is nowhere near as good at it as malting.
If you want to use very large adjunct loads (say >20%) its worth digesting your adjunct. I just put it in a stock pot with a little malt (say 10%) and about 4 times the grist weight in water, put on the stove top set to low and let it heat slowly from tap temperatures to a simmer over a couple of hours. Then just mash that lot in, the maths to calculate strike water temp get a bit esoteric but on a Braumeister it’s very easy.
Mark

PS just note that Glucanase likes the pH pretty low, the peak is around pH5, if you are using lots of adjunct mashing in at a lower pH might help.
M

 

[tubbsy]

Thanks Mark.

I did crush the NEIPA grains slightly larger than the bitter. My thinking was to reduce flour to reduce the chance of a stuck sparge.

How would I go step mashing on a 3V system? Could I just mash the wheat and oats with some of the malt, then periodically add boiling water to increase temps before adding the rest of the malt?

And now that you mention it, I have digested adjuncts before when using a lot of raw wheat. I bought it to a boil, wrapped in a blanket and left overnight before adding it to the mash. Will have to remember that for next time.

 

[MHB]

Get back to you on that, but yes you can get a couple of steps with hot water additions.

On digestion, it’s important to have some enzymes (not available in adjunct) and to let them work on the Glucan and Protein, so better to mash them in cold and warm slowly so the enzymes do their thing, then gelatinise. Before mashing in.
Mark

 

[duncbrewer]

The other thing that is different is your hop bill I suspect. NEIPA loads of hops, Bitter much less.

Realise that this will only contribute to your losses post boil.

I use 10 ml of glucanase enzyme in a 25 litre mash if lots of adjuncts. I then put the oats and wheat in with this at 50 celsius and then bring it up to dough in temperature slowly. Instructions say it is denatured at 85 celsius. Peak performance at 60 celsius and pH 5.5.
I've found it very useful and it doesn't add volume which oat hulls do if you are tight on capacity and doesn't absorb liquor which oat hulls do a bit.