Decoction thumbs up/down.

[das alte]

Wobdee,

Aeration causes issues. The decoction method drastically reduces high side aeration in the mash that is boiled. The O2 trapped in the husk is boiled away. The grain bed stratifies evenly.
I have an air stripper installed on the water feed to the kettles. It's basically, a vortex tube with an auto-vent on top. They're used when O2 is an issue in feed water. When the boilers are full of water, the water is brought to boiling. Starting from the time when the pump has water to it the water is recirculated through the vortex and back into the boilers. O2 still exists just not as much. I don't slop hot mash during transfer or do I slop water into any kettle that holds hot mash. In my opinion, brewers that are taking into consideration high side aeration during mash rest periods is great!!

Kettles are jacketed or direct fired to eliminate extended recirculation of mash liquid through the grain bed. It has to do with a type of thing called over sparge. The only time when mash liquid is recirculated is at the end of the brewing process, during vorlauf or when the brewer wants to crank up the OG of the first few gallons of extract to make high octane or to maybe, blend. Recirc is limited to 10 to 15 minutes. In my opinion, a system that circulates boiling water through a heat exchanger inside of the mash tun would be great for maintaining very close temperature during a rest. But, if it takes 20 or 30 minutes to raise mash temperature from a protein rest to a maltose rest temperature, etc., it's on the slow side.
If mash isn't boiled there won't be a thick layer of mud on the grain bed, it's in solution. But, once in a while mother Nature helps out and a small amount of goop will form on top of the grain bed with infusion, with some malt more so than others.
When a rest at 122F is performed on the entire grain bill for twenty minutes it's too much. Ramp up time needs to be considered, as well.
The beer will be clear, but it will be thin because protein is lacking. The positive impact is that the beer will be very stable, there isn't any goop left to drop out, which is great for the hops. The higher the percentage of protein in the malt the shorter the rest period should be or it should be limited to a small portion of the mash when a 20 minute rest is used. Wheat and six row are very close in protein percentage and wheat malt is known for causing haze, six row is, too.
How much finings are added and if they are, why?

George Fix invented the step mash method in the 80's. I find it interesting that throughout all the years of brewing beer that no one prior to Fix came up with the method. There hasn't been too much that hasn't been tried out since the founding of the IOB.
.

 

[GFHomebrew]

@das alte
Hey alt man what do you think about decocting this brew below I'm just putting it out there?
Reason being I've read some porters to boil down 1-2 gallons of first runnings untill thick and syrupy then returning this to the kettle.

So you see my reasoning if I mash in for 20-30 min at mid range infusion then pull off a thick decoction and boil this for the duration of the mash I may achieve a similar result as boiling some first running plus extract more glucose and Amilo pectin? I've got single infusion 66c 60min 30min 71c then mash out/sparge @75c. What's your 2c on this Das Alte or anyone for that matter .
https://www.brewersfriend.com/homebrew/recipe/view/495978/ben-s-porter-

Oh third observation from that first decoction brew was lots of trub in my fermentor up to the three liter Mark on my bucket 2 inches ish. My theory is that brown muck that usually settles atop of the mash has filtered into my brew. I biab so the grain bed isn't really such because I disturbed it when lifting out the bag. I guess it's all that protine that has settled in the fermentor?

 

[J A]

If mash isn't boiled there won't be a thick layer of mud on the grain bed, it's in solution. But, once in a while mother Nature helps out and a small amount of goop will form on top of the grain bed with infusion, with some malt more so than others.
When a rest at 122F is performed on the entire grain bill for twenty minutes it's too much. Ramp up time needs to be considered, as well.

I do multi-temp infusion and I've been using some Czech floor-malted Pilsner that's excellent malt. I use a recirculating system with a bag as well as a false bottom. When I get to mash-out temp I turn the pump down pretty low and let it recirculate slowly for 10 or 15 minutes to settle the grain bed before I start trickling wort into the boil pot. The wort is running very clear by the time it hits the boil pot and when it gets down to a proper level over the grain bed I start running 170 degree water for a 20 to 25 minute sparge. By the time it drains below the top of the grain bed there a nice thick layer of gunk on top. I don't doubt that I'd get some added benefit from decoction, but this method has been giving me wort that absolutely water clear by the time it gets to the fermenter.
I generally tend to do a short protein rest of 10 minutes before I start thinning the mash and and raising the temp for a step-infusion.

 

[wobdee]

Wobdee,

Aeration causes issues. The decoction method drastically reduces high side aeration in the mash that is boiled. The O2 trapped in the husk is boiled away. The grain bed stratifies evenly.
I have an air stripper installed on the water feed to the kettles. It's basically, a vortex tube with an auto-vent on top. They're used when O2 is an issue in feed water. When the boilers are full of water, the water is brought to boiling. Starting from the time when the pump has water to it the water is recirculated through the vortex and back into the boilers. O2 still exists just not as much. I don't slop hot mash during transfer or do I slop water into any kettle that holds hot mash. In my opinion, brewers that are taking into consideration high side aeration during mash rest periods is great!!

Kettles are jacketed or direct fired to eliminate extended recirculation of mash liquid through the grain bed. It has to do with a type of thing called over sparge. The only time when mash liquid is recirculated is at the end of the brewing process, during vorlauf or when the brewer wants to crank up the OG of the first few gallons of extract to make high octane or to maybe, blend. Recirc is limited to 10 to 15 minutes. In my opinion, a system that circulates boiling water through a heat exchanger inside of the mash tun would be great for maintaining very close temperature during a rest. But, if it takes 20 or 30 minutes to raise mash temperature from a protein rest to a maltose rest temperature, etc., it's on the slow side.
If mash isn't boiled there won't be a thick layer of mud on the grain bed, it's in solution. But, once in a while mother Nature helps out and a small amount of goop will form on top of the grain bed with infusion, with some malt more so than others.
When a rest at 122F is performed on the entire grain bill for twenty minutes it's too much. Ramp up time needs to be considered, as well.
The beer will be clear, but it will be thin because protein is lacking. The positive impact is that the beer will be very stable, there isn't any goop left to drop out, which is great for the hops. The higher the percentage of protein in the malt the shorter the rest period should be or it should be limited to a small portion of the mash when a 20 minute rest is used. Wheat and six row are very close in protein percentage and wheat malt is known for causing haze, six row is, too.
How much finings are added and if they are, why?

George Fix invented the step mash method in the 80's. I find it interesting that throughout all the years of brewing beer that no one prior to Fix came up with the method. There hasn't been too much that hasn't been tried out since the founding of the IOB.
.

Your air stripper sounds interesting. I've read and looked into similar methods but found it cheaper for me and my small batches to just pre boil all my brewing water for 5 min to eliminate O2 then immediately chill down to dough in temp. This alone makes a huge difference in retaining malt character IMO. O2 damage can happen within minutes of mashing in with O2 rich water, this is why I brought this up, I think many don't see much difference in decoction because the malt is damaged right off the bat.

 

[das alte]

It may be difficult to dial in Porter. Was the person who wrote the story on Porter alive during the time when the Porter was produced? Was he a pal of a brewmaster that made Porter who shared his secrets with him? They're stories created for marketing purposes, only.
Marris Otter is a newer malt and maybe it wasn't around during the time when the beer in the story was produced.
Marris Otter and Golden Promise are distillers malt, why use them for making Ale and Lager, anyway? The malt that another brewer is spoiled on is the same type of malt. Enzymes are needed. That's why enzymes are produced. Since, HBSs do not sell the variety of enzymes that malt may need, it is apparent that the malt they sell is so good that they don't need to sell enzymes. No wonder brewers and craft brewers who purchase malt from an HBS wins medals, the malt is perfect!

I don't brew Porter any longer, it is too difficult for me. I really enjoyed the challenge and miss producing Porter and Doppelbock styles of beer. I hope that it works out for you.
Three separate mash temperatures are used in three separate mash tuns. 150/153, 155/158 and 160F>. Each are decoctioned, lautered, boiled separately and blended.

Here's what I would do:
Scrap the Marris Otter and find malt with a protein percentage of eight to 10 and Kolbach 36 to 40.
Weyermann floor malt. If you want to try an interesting malt, try Crisp's Euro Pils.

Boil the specialty malt separately and use the mash for raising main mash temp. Be careful with boiling up specialty malt, it becomes aggressive in flavor. Adjust pH in the main mash after the specialty malt is added before boiling another decoction. Stick a 130ish rest in, too. I understand what you are attempting.
In the method that you explained; when the first decoction is removed, Alpha will be busy for 20 minutes in the main mash pumping out glucose and not so much sweet sugar. Depending on the malt, Beta may not exist and the glucose will remain as it is. Then, to create melanoidin it takes about one hour of boiling the mash, not taking into consideration of the time needed to increase the temperature of the decoction to boiling. That is a long time for enzymes to last with enough content left to do anything when dextrinization temp is hit, 71C.
When the main mash is at 66C remove the first decoction, don't wait 20 minutes. Raise the decoction to 162F and rest it for 20 minutes. Boil it for an hour. Even, then, enzymes will be active for over an hour in the main mash. That is the reason that I recommend to screw with the first decoction when enzymes are inactive in the main mash. If it isn't done in that manner too much is taking place in the main mash which may cause a balance that should occur, not to occur the way that it should later on.
Marris Otter will need an enzyme mixture added twice, maybe three times, an Alpha-Beta mix and an Alpha-Proteinase-Beta Glucanase mix if Ale is going to be produced.

It is better to rack the wort off the top of the goop before adding yeast. It's an extra step and precautions have to be taken but, that's part of brewing beer. Or, allow the goop to remain and pretend that it's beneficial for yeast reproduction.
Why don't you scrap the bag and purchase a lautertun? Trying to adjust a brewing procedure and make it adapt to a type of brewing system that isn't cut out for it makes it difficult. It can be frustrating, as well. Equipment not suitable for using the decoction method with can be a source of problems. Line up all of the ducks and trying to make the decoction method work becomes a task. Too many open ends that can't be controlled. Like what takes place during dunking a bag of silt, protein mud and beta glucan laden mash a few times and then squish the bag to grab every drop of liquid. But, use a method that is known for producing pristine wort? To each, his own. I have a five vessel system. Although, there is more equipment involved, it is needed to make the process as lean as possible. It takes that much stuff to make brewing with the decoction method easier and very consistent.
The bags back in the day weren't anything like the mesh sacks today. They were double wall canvas cylinders with stainless mesh sewn in one end. A steel ring was sewn in the top and bottom to keep the cylinder shape and hoops along the top fastened the cylinder to a container. Fly sparged instead of dunk and squish. The draw back was that it held only 12 pounds of grain. In the real world they are used for feeding horses. I watched "Quagmire, Down Under" and noticed there were a lot of horses Down Under. Look around, maybe a feed store has a feed bag. They worked really well!!

 

[das alte]

Wob,

I agree with you. I am a strong advocate for boiling the brewing water before using it.

 

[Nosybear]

I'd love to see the design of that air stripper. All references I can find to air stripping talk about stripping volatile compounds from water using air. Boiling strips most (but not all) air from water (or wort). Even heating to 160 degrees strips most - checking the engineerng toolbox, at 160 degrees F the volume of air is 0.0079 times that of the water, or less than 1%. Oxygen is 20% of that, so you have .0016 liters (gallons) of O2 per liter (gallon) of water. That's 0.2g of oxygen per liter of mash. If beer is that sensitive to oxygen, I don't know how we've been making it for over 5,000 years, most of the time not even knowing what yeast was.

 

[Ozarks Mountain Brewery]

I've found that the 60 or even 90 minute boil doesn't always pull all the oxygen out of the wort especially if its injected by poor handling of the water and mash, all kinds of issues occur by splashing and bubbling of water and wort before the mash and even in the boil, since I use a three kettle herms system now I've really improved my beer by eliminating all splashing of bubbles while transferring anything through tubes hoses and pipes, even ball valves will spray water when half closed creating turbulence and injecting air into what ever your moving, I can attest that it can be a problem if not carefully managed

 

[Nosybear]

I've found that the 60 or even 90 minute boil doesn't always pull all the oxygen out of the wort especially if its injected by poor handling of the water and mash, all kinds of issues occur by splashing and bubbling of water and wort before the mash and even in the boil, since I use a three kettle herms system now I've really improved my beer by eliminating all splashing of bubbles while transferring anything through tubes hoses and pipes, even ball valves will spray water when half closed creating turbulence and injecting air into what ever you moving, I can attest that it can be a problem if not carefully managed

That's a sensible precaution. I'm a buckets and cooler guy myself and take the same precautions to avoid splashing. But obsessing over a couple milligrams of oxygen? If that makes a difference, someone must be a hell of a lot better brewer than I am to detect it. My general response to issues like this is a shrug of the shoulders and a hearty, "it's your beer, dude." But we have a lot of beginners here, people who can't even control their fermentation temperature. I want to be clear: By the time you're to the point where a bit of oxygen on the hot side makes an appreciable difference in your beer as determined by a blind triangle test - not your own evaluation - then you really should be brewing professionally because, guess what, the pros don't even obsess over it. Think about it this way: Yes, there's a possbility of some oxidation in the mash. There's very little oxygen and very little time for the reactions to occur. You boil out almost all of the oxygen, then you add it back for the yeast. Do you obsess over the 30 minutes to an hour or so it takes for the yeast to scavenge the oxygen you've added? I agree with OMB: Take reasonable precautions on the cold side and any difference in outcome may first present itself a year or so after bottling. By the way, I have some three year old beers that show no signs whatsoever of oxidation. The malt flavors are still great. I do not take any precaution whatsoever against oxidation on the hot side.

But, as stated earlier, it's your beer, dude.

 

[GFHomebrew]

Well I guess I'll just use simple infusion mash with me horse Feed bag then .

 

[Nosybear]

Well I guess I'll just use simple infusion mash with me horse Feed bag then .

Long as it works. My setup is pretty primitive. I keep trying to get the guys at Ruby Street to get me a smoking deal on one of their rigs but until I can get Jim and Jay talked into it, I'll keep schlepping kettles and mash tuns. And making award-winning beer.

 

[GFHomebrew]

Long as it works. My setup is pretty primitive. I keep trying to get the guys at Ruby Street to get me a smoking deal on one of their rigs but until I can get Jim and Jay talked into it, I'll keep schlepping kettles and mash tuns. And making award-winning beer.

Yeah that is what it all boils down to Nosey.

 

[wobdee]

That's a sensible precaution. I'm a buckets and cooler guy myself and take the same precautions to avoid splashing. But obsessing over a couple milligrams of oxygen? If that makes a difference, someone must be a hell of a lot better brewer than I am to detect it. My general response to issues like this is a shrug of the shoulders and a hearty, "it's your beer, dude." But we have a lot of beginners here, people who can't even control their fermentation temperature. I want to be clear: By the time you're to the point where a bit of oxygen on the hot side makes an appreciable difference in your beer as determined by a blind triangle test - not your own evaluation - then you really should be brewing professionally because, guess what, the pros don't even obsess over it. Think about it this way: Yes, there's a possbility of some oxidation in the mash. There's very little oxygen and very little time for the reactions to occur. You boil out almost all of the oxygen, then you add it back for the yeast. Do you obsess over the 30 minutes to an hour or so it takes for the yeast to scavenge the oxygen you've added? I agree with OMB: Take reasonable precautions on the cold side and any difference in outcome may first present itself a year or so after bottling. By the way, I have some three year old beers that show no signs whatsoever of oxidation. The malt flavors are still great. I do not take any precaution whatsoever against oxidation on the hot side.

But, as stated earlier, it's your beer, dude.

I consider Narziss, Kunze, Fix and Blamforth all pros and there are many references from them on hot side O2 damage. Yes, there are many ways to brew and its not like you need to obsess over O2 to make good beer, there are plenty of other areas in the brewing process that can make or break your brew. I look at it like it's my hobby and just one of the many little things that add up to make the beer I like.

 

[KC]

Oxygen uptake behaves differently at homebrew level than it does at pro scale. It's much easier to manage with very large vessels. Air exchange is factored by the ratio of liquid volume to exposed surface area. That ratio decreases as batch size goes up.