Loss of Diastatic Power from Toasting Malt

[dmtaylor]

Hey guys, I'm resurrecting this necro-thread, as my local club is throwing a so-called SMASH beer competition (single malt and single hop), and I aim to win. As an experiment, I have decided to try to attempt to make a beer of 100% home-roasted diastatic amber malt. And I have a pound of Tettnanger laying around so I'll probably use that, with a lager yeast, to make some manner of a dunkel or bock. If you all have any experiences to share, I am all ears... at least for the next couple of days. I will probably bake / "roast" the malt on Wednesday 9/29, and brew on Thursday evening 9/30, as I will be gone over the weekend.

Based on a wee bit of online research, besides finding this thread (which is really awesome), I found the following link:

https://brewerylane.com/beer/beer-learning-centre
Based on this, my "Plan A" proposed process looks a little something like this:

1) Place the malt into 9 x 13 inch pans as necessary, aiming for a depth of about 1.5 to 2 inches. I will NOT be stirring periodically during the bake. I'm doing this on purpose to try to roast the corners and edges of the grains a little more then the insides -- call me crazy but I actually want my malt to end up NOT homogeneous. If it's a little more toasted in the corners, but the insides still have more enzymes, great!

2) Set oven to 170 F (the lowest allowed on my oven) and bake for about 15 minutes.

3) Raise oven to 200 F for 30 minutes.

4) Raise oven to 230 F for 30 minutes.

Done.

OR, would perhaps "Plan B" turn out better? It would certainly be easier. It's based on a different link, which includes really cool experimental data suggesting that malt roasted at 390 F for 45 minutes still has a tiny bit of enzymes?!

http://edsbeer.blogspot.com/2015/02/making-diastatic-brown-malt.html
So for this one I'd propose:

1) Same 2-inch depth in pans.

2) Set oven to 375 F and bake for 40 minutes. Slightly less than the limit to try to ensure enzyme preservation, and who knows, maybe my oven (or yours) is a little "fast" (i.e., hotter than it reads).

Done.

Some sources suggest aging the roasted malt for ~2 weeks prior to use, but others say there are things to be gained by using it right away. In any case, I don't have the luxury of waiting -- the beer has to be ready to drink by first week of November. So I'm brewing right away no matter what.

Thoughts!? I'll be sure to update later on appearance, aromas, efficiency, attenuation, flavor, etc.

If anyone is interested...

I actually ended up doing a hybrid of both Plans A & B. After starting with Plan A... the effect was basically nil, undetectable. Malt still tasted the same as when I started, and was still pure white inside the kernels, as if all I had done was dry out the malt a bit.

So, I decided to crank up the heat to 375 F, not for 40 minutes, but just 20 minutes. This definitely had a real impact. Very quickly I experienced toasty aromas coming forth from the oven. After the 20 minutes was over, I removed the toasted malt from the oven. Only on the top surface are the husks visibly much darker, but underneath they are only "moderately" darker than when I first started, which makes sense. When splitting the kernels open, I am able to detect just a very very faint tan tinting, no longer pure white.

So, tomorrow I shall brew with this toasted malt at 100% of the grist, and hope there is some enzyme content remaining for conversion. I do plan for a "long" mash of about 75 minutes, hopefully that will help too (-- usually I mash for 45 minutes, based on MUCH experimentation and experience for >130 batches). If my efficiency or attenuation is poor, I guess we'll have our answer about diastatic power after 20 minutes at 375 F, but I'll just go ahead and ferment it out regardless because I'm crazy like that.

 

[TheMadKing]

If anyone is interested...

I actually ended up doing a hybrid of both Plans A & B. After starting with Plan A... the effect was basically nil, undetectable. Malt still tasted the same as when I started, and was still pure white inside the kernels, as if all I had done was dry out the malt a bit.

So, I decided to crank up the heat to 375 F, not for 40 minutes, but just 20 minutes. This definitely had a real impact. Very quickly I experienced toasty aromas coming forth from the oven. After the 20 minutes was over, I removed the toasted malt from the oven. Only on the top surface are the husks visibly much darker, but underneath they are only "moderately" darker than when I first started, which makes sense. When splitting the kernels open, I am able to detect just a very very faint tan tinting, no longer pure white.

So, tomorrow I shall brew with this toasted malt at 100% of the grist, and hope there is some enzyme content remaining for conversion. I do plan for a "long" mash of about 75 minutes, hopefully that will help too (-- usually I mash for 45 minutes, based on MUCH experimentation and experience for >130 batches). If my efficiency or attenuation is poor, I guess we'll have our answer about diastatic power after 20 minutes at 375 F, but I'll just go ahead and ferment it out regardless because I'm crazy like that.

Thanks for reporting back! I plan on toasting 2 lb of American 2 row this weekend to use in a Scottish ale down the line so I will definitely start with the higher temperature

 

[Stormcrow]

You guys need to let us know how these turn out. I'm super interested in home malting and roasting.

 

[dmtaylor]

Thanks for reporting back! I plan on toasting 2 lb of American 2 row this weekend to use in a Scottish ale down the line so I will definitely start with the higher temperature

I too am toasting American (Briess) 2-row Brewers malt for this experiment. I have toasted Maris otter malt in the past at about 350 F for 20 minutes and the result tasted positively like PEANUTS. In fact, the reason I am using American 2-row this time is to see what difference it makes. And I chose not to use German Pilsner malt because to my palate the raw grain seems grassy and not the same breadiness that I get from American, and I did not want to risk having any grassiness in this particular batch.

My toasted American malt today tastes like… toast and Cheese-Nip crackers, but without the cheese! To my palate, this is right in line with how I perceive raw Vienna malt. So I have high hopes.

 

[Silver_Is_Money]

If you look at my avatar photo you can easily see that toasting Vienna malt for 60 minutes at 250 degrees F. made for a distilled water Mash at about 18 SRM as to it's color, and also a measured 5.07 pHDI. I can't imagine what the SRM color and pHDI results would have been if this had been done at 375 degrees F. But I do know that a mash made from straight untoasted Vienna malt yields closer to a ballpark 6 SRM final color.

 

[dmtaylor]

We shall soon find out. I will post pictures late tonight, probably around 11pm CDT (Chicago time). Keep in mind, this is toasted Briess brewer's 2-row malt, which I imagine will turn out similar to Vienna or a light Munich of 10-15L. I'm basically aiming for a Vienna or Munich dunkel style, so a copper-ish sort of color would be my goal. I think I'll get there.

 

[dmtaylor]

Mash is halfway done. Conversion is DEFINITELY happening just fine. Nice toasty and nutty aromas, and deep amber to light copper color. Began with a pH goal of 5.6. Actual is 5.3. So indeed, the pH is much lower than a standard base malt. I am going to let it ride at 5.3.

 

[dmtaylor]

All done. OG is 1053 for a brewhouse efficiency of 81%. Not too shabby. The wort tastes quite toasty and slightly burnt but I’m OK with that. Maybe toasted malts really do benefit from a week or two of aging to mellow out. But I think this is going to be good anyway. I love the deep orange to copper color. I figure it is about 15 SRM and 15 L for the malt itself. Sparging was kind of a pain. After the crush I noticed the husks were pretty well destroyed, must’ve been due to the drying process yesterday. Next time I would condition the grains to avoid this. Overall a pretty good brew day.

Some pics. The lighting is bad. The lightest color picture where held up to a light bulb seems maybe closest to the actual color, or it is someplace in between. Do you like my pickle jar fermenters? I use them on almost every batch. One jar has S-189 at room temp, the other Diamond lager at about 60 F or as cold as the basement will go this October (in Wisconsin).

Cheers.

 

[TheMadKing]

I'm doing my first test today. As a baseline I'm following the advice of Randy Mosher and I soaked the malt for a few minutes, and I'm baking for 40 minutes at 375.

So far so good and it smells great

 

[TheMadKing]

I'm doing my first test today. As a baseline I'm following the advice of Randy Mosher and I soaked the malt for a few minutes, and I'm baking for 40 minutes at 375.

So far so good and it smells great

The grain picked up a nice biscuit/light toast flavor at 40 minutes but the moisture content is still quite high.

It tastes great but I'm worried about its shelf stability with the moisture this high. It's still cooling so I hope it continues to dry

The flavor is best compared to melanoidin I think

 

[TheMadKing]

Ok some actual data:

This malt is no longer diastatic. A mini mash of .5 hours fine grind resulted in a positive iodine test.

The color is much less than you reported @dmtaylor in your batch despite double the time in the oven.

The mash pH is 5.2 using my filtered home water (not DI. residual alkalinity is 24ppm)

The mini mash smells like medium dark toast, and tastes like dry toast with almost no sweetness or Caramel flavors at all

So I'm chalking this up to the water soak before I started. I think I will prefer the results with toasting dry malt

 

[Miraculix]

The grain picked up a nice biscuit/light toast flavor at 40 minutes but the moisture content is still quite high.

It tastes great but I'm worried about its shelf stability with the moisture this high. It's still cooling so I hope it continues to dry

The flavor is best compared to melanoidin I think

You've been basically mashing partially the grains while baking. The enzymes defolded and therefore became vulnerable to temperature. My guess is that there is now no diastatic power left because of the water.

Edit: parallel post

 

[TheMadKing]

You've been basically mashing partially the grains while baking. The enzymes defolded and therefore became vulnerable to temperature. My guess is that there is now no diastatic power left because of the water.

Edit: parallel post

Yep agreed, I'm doing a second batch right now with no water

 

[TheMadKing]

Ok one more to report back:

3lb american 2-row toasted at 300F for 55 minutes

smells like dark bread crust, or almond roca (no not like almonds, just very nutty with a hint of chocolate)

The mini mash sat for 30 minutes and still resulted in a positive iodine test indicating that this malt is also no longer diastatic. I can taste a hint of sweetness though, so perhaps there is still a small amount of enzymes left. The color is medium brown, I'd estimate the liquid color to be about 15 SRM. It tastes toasty and bready, and just hint of roast.

I would definitely call the resulting malt "brown" but unfortunately I have denatured the majority of the enzymes. I think @dmtaylor you managed to strike the right balance on your first shot, and you may have toasted a bit lighter than I'm going for too. I'm overall happy with the resulting malt, and I think it will make a nice addition to my scottish ale, but it's not suitable for a SMASH beer any time soon.

In keeping with @bracconiere s post earlier, I will try a low and slow method too where I roast it at 185F for several hours and see what that gets me too

 

[dmtaylor]

The mini mash sat for 30 minutes and still resulted in a positive iodine test indicating that this malt is also no longer diastatic. I can taste a hint of sweetness though, so perhaps there is still a small amount of enzymes left. The color is medium brown, I'd estimate the liquid color to be about 15 SRM. It tastes toasty and bready, and just hint of roast.

In keeping with @bracconiere s post earlier, I will try a low and slow method too where I roast it at 185F for several hours and see what that gets me too

Great experiment, thanks for sharing.

I wonder if 30 minutes wasn't long enough to run an iodine test. I had conversion happening within a few minutes, but I didn't do any iodine tests. If I were expecting an iodine test to come out clean, I would have waited at least 75-90 minutes for that. I mean, I know when I am using Munich malt for the main base malt, I need to extend my normal mash time of 45 minutes to at least 60-90 minutes because there is in fact lower diastatic power in these darker base malts. If I ran an iodine test at 30 minutes, I would absolutely expect a positive result. What I'm saying is...... you might still have enzymes in there... AND I think an iodine test is of very low value, unless I was running a mash of say 2-3 hours when I might expect it to come out totally negative. Any time before that.... not so much. The 75-90 minute point might be the point of being "good enough" for decent efficiency and fermentability, regardless of iodine test.

I do think a very loooong roast at 185 F should give interesting results. But just might take 3, 4, 5 hours at that temperature to get much impact.

 

[dmtaylor]

And all that being said......

I fear my attenuation is going to suck. Currently fermentation is slowing way down. My Tilt right now is saying 1.029 on the batch fermented with Diamond (started at 1.053). I sure hope it keeps on chugging for a while longer as I would like it to go under 1.020. But at this point, I am beginning to have doubts that it will happen. So I fear I did not mash long enough. Sure, starches were breaking down into complex sugars and dextrins, but.... much of these cannot be fermented by beer yeast. Dagnabbit. I hope my fears are untrue. But I'm often correct about such things. Time will tell.

 

[Silver_Is_Money]

I'm doing my first test today. As a baseline I'm following the advice of Randy Mosher and I soaked the malt for a few minutes, and I'm baking for 40 minutes at 375.

So far so good and it smells great

Soaking the malt before roasting it may put you on the path to producing a caramel/crystal type malt.

 

[bracconiere]

I will try a low and slow method too where I roast it at 185F for several hours and see what that gets me too

i usually leave it at 170f overnight, the oven auto shuts off after 12 hours.....but my oven creeps up to 200f maybe a couple degrees hotter. so i'd recommend starting at 170f, wait 2-3 hours, shoot an IR temp gun at the grain. and adjust from actual temp...


my understanding is that 200f kilning makes basically dark munich...and i've used it for 4 years before that post, and know it has plenty diastatic power...


i'd describe the taste, to the best of my ability, decievingly light, and carmel nutty, for how dark it is....

you're using already kilned malt though, so YMMV...

 

[TheMadKing]

Soaking the malt before roasting it may put you on the path to producing a caramel/crystal type malt.

I thought the same thing, but then he specifies a process for creating crystal malt which requires soaking for 24 hours.

I think moisture can be used without creating crystal malt, but I only soaked for 5 minutes and it was too much. I think a light spritz of water, or even a bowl of water in the oven to increase the humidity might yield better results

 

[TheMadKing]

Now I fully understand why there are recommendations to rest your malt for a couple weeks

I stashed those (and a third batch of toasted pils. 30 min at 400F, still not able to self convert, but very nice smelling) in paper bags in a closet and shut the door.

30 hours later I opened the door to look for something and the whole closet is absolutely OVERPOWERING with the smell of the malt. It smells very similar to overheated popcorn and isn't entirely pleasant, so I think that'll be those volatiles coming out.

 

[Silver_Is_Money]

I still think its best to hold the temperature at (or below) 250 degrees F., and vary the oven time, rather than trying to hurry things along by bumping temperatures into the 350-400 degree F. range.

One major caveat: Conventional cooking ovens are notoriously terrible at holding temperature at or near the desired set point temperature. This alone makes it difficult to equate one persons malt toasting experience with another's.

 

[Miraculix]

I still think its best to hold the temperature at (or below) 250 degrees F., and vary the oven time, rather than trying to hurry things along by bumping temperatures into the 350-400 degree F. range.

One major caveat: Conventional cooking ovens are notoriously terrible at holding temperature at or near the desired set point temperature. This alone makes it difficult to equate one persons malt toasting experience with another's.

You'd actually need to keep a thermometer inside all time to be able to reliable tell the ongoing temperature.

 

[dmtaylor]

My fermentation appears to be stalled at 1.027, that's 50% attenuation from OG 1.053. Dagnabbit. I'll have to think about how best to resolve. I really don't like the idea of adding some type of enzymes, but now I have to give it more serious thought. Temperature has been stable at 64-65 F so that's not the issue. I just didn't mash long enough for the very low amount of enzymes that were in there.... enough to convert starch to dextrin, but not enough to convert dextrin to simple sugar. I'm disappointed.

 

[TheMadKing]

My fermentation appears to be stalled at 1.027, that's 50% attenuation from OG 1.053. Dagnabbit. I'll have to think about how best to resolve. I really don't like the idea of adding some type of enzymes, but now I have to give it more serious thought. Temperature has been stable at 64-65 F so that's not the issue. I just didn't mash long enough for the very low amount of enzymes that were in there.... enough to convert starch to dextrin, but not enough to convert dextrin to simple sugar. I'm disappointed.

A tiny amount of glucoamylase will get it moving again. You'll need to cold crash and keg it when it hits the FG you want though because otherwise it'll ferment totally to 1.000

 

[TheMadKing]

I want to resurrect this thread once more and report back.

The Scottish Ale competition was a couple weeks ago and I'm sorry to report I didn't win. I took 2nd place out of 10 entries with a score of 38.

I ended up using 1lb of the toasted pils malt in a more conventional grain bill and I think it was too much. The resulting beer was very heavy in the mid-range melanoidin flavors and had my and Miraculix's dreaded marzipan flavor. I also suspect that my addition of 2lb of simple sugar caused a more estery beer which is the root of that marzipan flavor.

Overall it was a good beer, and i think my home toasted malt was a successful specialty grain, but i have not yet achieved a self converting brown malt.

I'll give it a few more shots though!

 

[Miraculix]

I want to resurrect this thread once more and report back.

The Scottish Ale competition was a couple weeks ago and I'm sorry to report I didn't win. I took 2nd place out of 10 entries with a score of 38.

I ended up using 1lb of the toasted pils malt in a more conventional grain bill and I think it was too much. The resulting beer was very heavy in the mid-range melanoidin flavors and had my and Miraculix's dreaded marzipan flavor. I also suspect that my addition of 2lb of simple sugar caused a more estery beer which is the root of that marzipan flavor.

Overall it was a good beer, and i think my home toasted malt was a successful specialty grain, but i have not yet achieved a self converting brown malt.

I'll give it a few more shots though!

The mazipan still is a big mystery to me... I've managed to lower it, but sometimes it still shows up. The last batch I've tasted it included invert sugar..... Hmmmmm....... You might be on to something with your ester theory.

At least I'm not alone with it.

 

[Miraculix]

How are you heating your mash when doing stepped mashes? You do stepped mashes, don't you?

 

[Misplaced_Canuck]

The mazipan still is a big mystery to me... I've managed to lower it, but sometimes it still shows up. The last batch I've tasted it included invert sugar..... Hmmmmm....... You might be on to something with your ester theory.

At least I'm not alone with it.

Very late to the game on this one... What percentage of home-toasted malt are you using?

 

[Miraculix]

Very late to the game on this one... What percentage of home-toasted malt are you using?

None, i think you might have addressed the wrong person.

 

[Misplaced_Canuck]

None, i think you might have addressed the wrong person.

Yeah, I was addressing to MadKing...