Yield on Malted and Unmalted Grain

[Dr Griz]

A recent disappointing all-wheat wash has had me pondering -- I figure I'd share my thoughts for the good of the order.

With almost 200 ferments under my belt, I've dialed in my mash protocols so that I can regularly expect 1.070 or better OG -- with glucoamylase, that gives me a healthy 9-10% ABV wash for my boiler. I could get higher efficiencies by changing my kit, but I reckon reliability is more important than chasing numbers.

This time, however, it came in at 1.055. The mash bill was 78% unmalted wheat and 22% malted wheat. An iodine test showed a full conversion. Mind you, 1.055 isn't exactly a catastrophe -- the white whiskey tasted pretty good, and is settled down for nice age on oak -- but it left me with a process riddle. PPG charts usually show wheat and barley as pretty much the same, easily enough to hit my 1.070 target. So what the hell happened?

A little while ago, I went down a rabbit hole on bushel weights of malted and unmalted grains (viewtopic.php?p=7791655#p7791655), and learned that unmalted rye and barley are surprisingly heavier by volume than their malted counterparts. Thinking about it, it makes sense -- a bit of googling tells me that unmalted grains are ideally stored at 12-13% moisture, while malts are stored at 4-6%. That difference in water weight (let alone whatever the malting process itself does) is gonna give malted grain more available sugar by weight than unmalted grain.

And sure enough, when I did the math, it worked out reasonably closely: Assuming a typical PPG for malted wheat at 31, the unmalted wheat would have to be at about 27.6 PPG to yield the OG I experienced. That's about 73% of malted wheat. Not too far from the standardized bushel-weight ratio of malted (34 lb/bu) and unmalted (48 lb/bu) barley.

I know, I know -- this isn't exactly new information. I found two threads from a few years ago that touched on these differences, but they didn't really dig into the numbers.

viewtopic.php?t=93346
viewtopic.php?t=86955

So I guess I'm wondering if this more or less fits your experience? And maybe more importantly, does anyone have more systematic numbers we can all use to predict our gravities? I've recently bought a proper grain mill, so I'm starting to use a lot more unmalted grain. Unfortunately, the kind of bushel-weight and PPG charts I can find online (including online calculators like Brewer's Friend) inevitably leave out a lot of the grains we all use, so I'm running off a pretty dismal sample size for dialing in my mash bills going forward.

[tommysb]

Hi Dr Griz -

Great timing - I'm going to mash about 140kg of unmalted wheat tomorrow, so I'll try to take some proper measurements that are hopefully useful to you, me and everyone else.

Anecdotally - I always felt that the yield was less than I 'expected' if I took brewer's malted barley as a benchmark. But the unmalted wheat cost a lot less, so it never really bothered me that much. In the future I will go through the process of trying to optimise and increase brewhouse and distillery efficiencies, so it will definitely be worth sharing some thought and observations here.

[Dr Griz]

I'll try to take some proper measurements that are hopefully useful to you, me and everyone else.

Excellent! I look forward to hearing how it compared to what you might have predicted for malted wheat!

unmalted wheat cost a lot less, so it never really bothered me that much.

Exactly. If my own experience is any indication, the cost difference far outweighs losses in efficiency. But it would be nice to be able to predict those differences with some reliability. Or maybe that's just my penchant for number-crunching trying to sneak in and ruin a perfectly good hobby.

[tommysb]

Another thing to consider is that malted barley (or wheat) is probably a variety bred for brewing, where starch content and so potential gravity is higher. Unmalted is probably (possibly?) an animal feed variety where higher protein and lower starch might be acceptable

[Dr Griz]

I've had the chance to work with a maltster a while ago, and I was surprised just how much difference there was between cultivars of the "same" 2-row barley. Some heritage varieties (like Maris Otter or Chevalier) are marketed as such, but there are several modern cultivars that are grown (and packaged) without clear labels, just as "2-row" or "pilsner" or "vienna." When you actually look at the spec sheets, there are some pretty big differences in starch, protein and fat content.

After all, the bushel weight "standards" are set by law, not by statistical analysis of the actual weight of a given year's barley harvest...

[bilgriss]

Because the unmalted grains are indeed heavier and denser, they take longer to cook and completely make starches available, to unlock their potential for enzymes also. A good grind helps.

[Bradster68]

https://onlinelibrary.wiley.com/doi/ful ... 02/jib.178
Not sure if this link will help. A very helpful friend from this forum "TB" sent me a while back. IV read it a few times.

[Dr Griz]

Because the unmalted grains are indeed heavier and denser, they take longer to cook and completely make starches available, to unlock their potential for enzymes also. A good grind helps.

That's a good point. I'm quickly learning that the shift from malt to unmalted grains involves more than one process change to maximize their potential. What struck me is that, after a good hard cook and a fine grind, there is still a significant difference in efficiency. I'm trying to figure out some rules of thumb for quantifying that difference for future mash bill design.

[Dr Griz]

https://onlinelibrary.wiley.com/doi/ful ... 02/jib.178
Not sure if this link will help. A very helpful friend from this forum "TB" sent me a while back. IV read it a few times.

Groovy. I found that my high-oat malt beers often had a much lower OG, which I assumed was because oats (or at least the oats I had) clearly had a much higher proportion of husk than barley malt. My oat malt stout manages to have a comparable mouthfeel and a much lower ABV than barley stouts.

I haven't (yet) done big oat mash bills for distilling, thought -- I've heard it contributes a silkiness to the final product that I'd like to try. I'm still recovering from my last all-rye mash, so it will be a minute before I jump with both feet into oats!

[Twisted Brick]

I'm quickly learning that the shift from malt to unmalted grains involves more than one process change to maximize their potential. What struck me is that, after a good hard cook and a fine grind, there is still a significant difference in efficiency. I'm trying to figure out some rules of thumb for quantifying that difference for future mash bill design.

In addition to being a tad lower than other grains, the PPG of oats is what it is. Even the potential from these two sources differ slightly.

https://beermaverick.com/fermentables/g ... ing-chart/

https://stillntheclear.com/moonshine-10 ... ppg-chart/

Experience will be your best guide.

[Bradster68]

I'm quickly learning that the shift from malt to unmalted grains involves more than one process change to maximize their potential. What struck me is that, after a good hard cook and a fine grind, there is still a significant difference in efficiency. I'm trying to figure out some rules of thumb for quantifying that difference for future mash bill design.

In addition to being a tad lower than other grains, the PPG of oats is what it is. Even the potential from these two sources differ slightly.

https://beermaverick.com/fermentables/g ... ing-chart/

https://stillntheclear.com/moonshine-10 ... ppg-chart/

Experience will be your best guide.

Well look who showed up. Your ears must have been burning TB. LOL.
I'm still waiting to run my unmalted oats.
Soon though. I'm just passing on what you've gave me.
Those links you may have sent me already,my phone got smashed (and that's all I use really is my phone).
So I've lost a lot. But I will definitely be saving these new ones. Thanks again twisted brick.

[Twisted Brick]

Well look who showed up. Your ears must have been burning TB. LOL.
I'm still waiting to run my unmalted oats.
Soon though. I'm just passing on what you've gave me.
Those links you may have sent me already, my phone got smashed (and that's all I use really is my phone).
So I've lost a lot. But I will definitely be saving these new ones. Thanks again twisted brick.

Yo Brad! I know! Life sure has a habit of getting in the way sometimes!

I forwarded the original email with the links to you. Any questions just holler.

TB

[Bradster68]

Well look who showed up. Your ears must have been burning TB. LOL.
I'm still waiting to run my unmalted oats.
Soon though. I'm just passing on what you've gave me.
Those links you may have sent me already, my phone got smashed (and that's all I use really is my phone).
So I've lost a lot. But I will definitely be saving these new ones. Thanks again twisted brick.

Yo Brad! I know! Life sure has a habit of getting in the way sometimes!

I forwarded the original email with the links to you. Any questions just holler.

TB

Your awesome TB thanks again for everything

[tommysb]

Hi Dr Griz -

Great timing - I'm going to mash about 140kg of unmalted wheat tomorrow, so I'll try to take some proper measurements that are hopefully useful to you, me and everyone else.

Anecdotally - I always felt that the yield was less than I 'expected' if I took brewer's malted barley as a benchmark. But the unmalted wheat cost a lot less, so it never really bothered me that much. In the future I will go through the process of trying to optimise and increase brewhouse and distillery efficiencies, so it will definitely be worth sharing some thought and observations here.

Hi -

This got delayed, and I'm afraid that the data is also a bit unreliable, as it wasn't me, but instead my colleague who ended up doing the mash. I came in the next morning, and did the measurements of the gravity.

Anyway, we mashed 140kg of unmalted wheat with 250L of water, and used extraneous alpha and gluco enzymes.

Mash was an infusion - heated water to 65c, and then added grains and enzymes. It was supposed to be circulated using a pump, but my colleague just stirred it, so I'm not sure of the enzyme distribution. Also not 100% confident about the mash infusion water strike temp - the data I was given was unclear.

Mash went on around 9.30-10pm at night, and I came in the next morning around 9am. I recirculated the mash for about an hour, which was now at about 40c.

Gravity was 1.060 - much lower than I would hope for this grain/water ratio (1.8L/kg grain). In the past, I was hitting similar gravity with 2.5 L/kg. So not quite sure what went wrong.

Anyway, we sparged it all out and it's fermenting now. I will add some more yield calcs when I get my next mash!

[Dr Griz]

Gravity was 1.060 - much lower than I would hope for this grain/water ratio (1.8L/kg grain). In the past, I was hitting similar gravity with 2.5 L/kg. So not quite sure what went wrong.

That does seem awfully low, but I reckon that's part of the point of this PPG exercise -- it's hard to know that the process needs adjusting if you don't have a reasonable expectation of what you're aiming for!

I'm afraid that the data is also a bit unreliable

I reckon one of the additional challenges of unmalted (and low diastatic grains in general) is that we can't leave as much to the grain itself -- even a small deviation in cooking or enzyme additions can have pretty big knock-on effects...

I don't know what limits you may have in your process (your reference to a "colleague" makes it sound like something more than just a hobby in the shed), but I find that when I've cocked up a mash that Angel Yellow Label can salvage things pretty well (but I ferment on grain, which gives me that option). In fact, that's part of what got me going on this whole unmalted wheat PPG business -- when I got a low SG, I figured I'd screwed up the mash and pitched YL instead of my usual yeast. When my yield off the still didn't get any better than my original projection, I had to start looking to inputs instead of process.

[tommysb]

It's JUST bigger than a hobby in a shed, but not by much. The direction of cashflow is still the same as it would be for a hobbyist .

I don't ferment on the grain, as the time and mess involved is not worth it IMO - I have to separate before distillation, and it's easier just to run out of a mash tun.

I am not too worried about the conversion in this case, as I fly sparged from a mash that had cooled to 40c, and so I believe that some enzymes will carry over into the ferment too; E,g, there;s a chance that anything unconverted that gets into the ferment will get converted over the next week or so.

In the long run I am going to move to malted grains, I just want to fill a barrel with unmalted wheat, so have a few of these mashes to get done in the meantime! I'll probaby run another mash next week - I will be more strict on pushing all protocols for efficiency and update some more figures here!