Decoction Question

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AnOldUR

AnOldUR

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It seems like I’m trying to make today’s brew session as difficult as possible. Going to try decoction to get step temperatures. The question; is there any advantage (or disadvantage) to thinning the mash as the temperature is increased?

I was giving some thought to adding 5 quarts of the thick mash decoctions to 2 quarts of water already at boiling in the pot and bringing this mixture back to a boil. The thought is that the thinner mash during saccrification will improve fermentables. And that the water in the decoction will reduce scorching. Is this an acceptable way to do this?

The beer is an IPA that doesn’t really need this process. I’m just looking for the experience.
 
AnOldUR said:
It seems like I’m trying to make today’s brew session as difficult as possible. Going to try decoction to get step temperatures. The question; is there any advantage (or disadvantage) to thinning the mash as the temperature is increased?

I was giving some thought to adding 5 quarts of the thick mash decoctions to 2 quarts of water already at boiling in the pot and bringing this mixture back to a boil. The thought is that the thinner mash during saccrification will improve fermentables. And that the water in the decoction will reduce scorching. Is this an acceptable way to do this?

The beer is an IPA that doesn’t really need this process. I’m just looking for the experience.
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I don't really think a thinner mash will "improve fermentables", as you say. It might reduce scorching, but you really should be stirring the whole time to take care of that anyway.

I'm also not so sure about your idea of adding the thick decoc portion of the mash to boiling water. When I do double or triple decoc mashes, for my first separation, I always bring the separated portion of the mash (about 1/3) up to 158 for 20 minutes to ensure that starch conversion is complete, THEN I boil. However, with your method, if you added the thick 1/3 directly to boiling water, it would probably denature your enzymes and leave you with a bunch more unconverted starches in the mash than you want.
 
As Evan! said, I wouldn't add your thick decoction to boiling water. You need to bring that portion of the mash to conversion temperatures and let it fully convert before you increase the heat to do your boil, if you add it to boiling water you run the risk of either over-shooting the conversion range or of denaturing all of the enzymes entirely.

You can run a thinner mash (in fact I usually do when decocting) so that the water loss during the decoction boils isn't as noticeable. Oh and scorching is a major issue so you have to stir all the time, there's just no getting around it. Using a nice heavy bottomed pot for your decoction kettle will help.
 
I thought that I read somewhere that the enzymes were mostly in the liquid portion of the mash which is left in the MLT. But I’ve also read to heat slowly, and/or like you say, to hold at starch conversion temperature before proceeding to the boil. For this session it will be best if I stick to the methods you’ve mentioned.

Mash thickness and it’s effect on fermentables is also something that I keep reading mixed opinions on. What I was thinking came from the quote below, but in reading closer, it’s not until over 2qts/lb that it becomes a factor.

Beerthoven said:
. . . As for the effect of mash thickness, here is what John Palmer has to say:

From How To Brew by John Palmer (Chapter 14, Section 6)
The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature.

Thin mash = more fermentable wort, ligher beer
Thick mash = less fermentable wort, sweeter, maltier beer.

It's interesting that English ales are mashed thick, but often (not always) at low temps (like 150 to 152, on average). The interplay between temp and thickness might be what gives English ales their unique malt character.
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The enzymes are indeed in the liquid, that's the other reason you don't want to use external hot water when you pull your decoction. If you do you won't have enough enzymes in the decoction kettle to convert the starch that is in there. You need to bring enough of the mash liquid to convert but not enough to remove the enzymes from the main mash.

With regards to mash thickness and decoction boils, you need to remember that you'll be boiling off a lot of the liquid so it won't end up being that thin anyway.
 
Greg Noonan has some great explanations of decoction mashing (NBLB). He states that you're only trying to "dextrinize" the decoction and, depending on the decoction (single, double, etc.) you only need to hold the decoction at 158dF for 10 minutes before heating to boiling.

You're right in reasoning that a thin mash increases fermentables. "A much thinner mash increases the proportion of maltose, and thus wort attenuation." (Noonan) However, I would shy away from thinning the decoction. Like others have said, you're going to have to stir constantly anyway, so scorching isn't really an issue. You can certainly thin your mash as you step up though. I don't see anything wrong with reducing decoction volume and supplementing said volume with boiling water, but it seems more complicated than what it's worth when you could just do an overall thinner mash.

If you're looking for higher attenuation, I'd go with a thinner overall mash and dial in your step temps. What's your grain bill for this and what is your planned decoction schedule?
 
menschmaschine said:
. . . . What's your grain bill for this and what is your planned decoction schedule?
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Reading a lot of sources and trying to piece together a plan can be confusing. In the HBT wiki I read about &#8220;German brewers often use a 2 step saccrification scheme&#8221; and wanted to incorperate it into this brew session. Foster&#8217;s Pale Ale had me convinces of the value of an acid rest of 104 degrees.

My original plan is below, but I was considering adding 2 quarts to the 2nd saccrification to get the mash thickness up to 1.5 qts/lb. The reason for not starting out with that thickness is that I&#8217;ve read that the earlier cooler steps benefit from a thicker mash.

There is just too much information my in head right now. Does any of this sound reasonable?



Ingredients​

12.50 lbs Maris Otter - Muntons
1.50 lbs Flaked Rye - Keystone
1.00 lbs Light Munich &#8211; Weyermann
1.00 lbs 20L Crystal &#8211; Briess
2.00 oz Centennial Hop Pellets &#8211; Alpha 9.5%
2.00 oz Amarillo Hop Pellets &#8211; Alpha 8.9%
1.00 tsp Irish Moss
1.00 tbs pH Stabilizer
Wyeast 1272 American All II (2nd Generation)
42 qts. filtered water



- Mash -​

Acid Rest
Target Temperature:100-105 degrees
Strike Temperature: 111 degrees
Infusion Volume:12 quarts strike water
Other Additions:1 tbspH Stabilizer
Mash Thickness:.75 qts/lb
Rest Time:30 minutes

1st Saccrification (infusion)
Target Temperature:138-143 degrees
Strike Temperature: 200 degrees
Infusion Volume:10 quarts infusion water
Other Additions:none
Mash Thickness:1.38 qts/lb
Rest Time:30 minutes (+ decoction boil)

2nd Saccrification (decoction)
Target Temperature:153-158 degrees
Strike Temperature: 210 degrees
Infusion Volume:6 quarts thick mash
Other Additions: 1 cup water
Mash Thickness:1.38 qts/lb
Boil Time:15 minutes
Rest Time: 45 minutes (+ decoction boil)

Mash Out (decoction)
Target Temperature:165-170 degrees
Strike Temperature: 210 degrees
Infusion Volume:6 quarts thin mash
Other Additions: none
Boil Time: 15 minutes
Rest Time:10 minutes



Edit: Heading out the door for HD. Found a deal on 50ft 3/8" copper for $33. Time for a longer chiller :rockin:


 
AnOldUR said:
Edit: Heading out the door for HD. Found a deal on 50ft 3/8" copper for $33. Time for a longer chiller :rockin:
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Where????? Is it a chain store? I'm looking for this myself!!!!

EDIT: Oh, duh! HD... you said Home Depot. I'm an idiot.
 
AnOldUR said:
Does any of this sound reasonable?
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Sure, but I'll start by quoting Noonan again:):

"Where the malt is well reasonably well modified and evenly crushed, however, the traditional three decoctions may not be necessary; even a single-decoction (or step) mash is never advisable with British ale or brewer's malts that have been thoroughly modified during malting and would be "over-modified" by exposure to low temperature rests."

So... does that mean that you shouldn't do a decoction at all with Marris Otter? I don't know what the negative results would be if you did. Maybe someone else can give light to that.

I noticed you're using pH stabilizer AND doing an acid rest. If you want to do the acid rest, I would check the pH after 20 minutes. If it's not at or below below 5.8, then I'd add the stabilizer. Otherwise you wouldn't need it. The rest of your schedule looks good as you are pretty much avoiding a protein rest, which you probably don't want to do with the Marris Otter anyway. You really aren't going to benefit much flavor-wise with doing the mash-out decoction. Mash-out decoctions are thin and don't contribute much to the "maltiness" of brewing with decoctions. So, if you have direct heat, etc., you may want to save the time and just step it up.

I'd love to hear about the deal you got on the copper coil at Home Depot. Do you think it's just a regional sale? I might go down to the HD near hear tomorrow and see.
 
menschmaschine said:
I'd love to hear about the deal you got on the copper coil at Home Depot. Do you think it's just a regional sale? I might go down to the HD near hear tomorrow and see.
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Just got back. My local (Flemington, NJ) Home Depot had a clearance at the $33 price, but was sold out. They called around and found the Phillipsburg store had them in stock. Somehow they got Phillipsburg to honor the price even though they weren't having the same closeout sale. (The manager at Flemington was a really cute girl and she knew the Phillipsburg manager.) It was over 20 miles one way, but it was a nice day to take the bike out. You might want to check out your local HD. For some reason, most of the NJ stores are no longer going to carry the 3/8” diameter in 50' lengths, so there closing them out.

Bad part is that now it’s too late to start brewing. I’ll use the rest of the day to get the chiller ready and line everything up for tomorrow.

Like you, Foster says that the 104 degree rest won’t have much effect on flavor, but it’s suppose to give you more consistent efficiency results regardless of where you buy your grain. I use a Rubbermaid cooler for my MLT so no direct heat. A lot of brewers here don’t have any use for mash out, but that is another place where you read conflicting information. Sometime I do it, sometimes not, but I figure that with the decoction mash out I won’t be taking away from my sparge water with another infusion.

My favorite part about this hobby is all the experimenting you can do with technique. (OK, I like the beer too.) This decoction thing is going to make for a long brew day, but I’m really looking forward to it.
 
menschmaschine said:
Sure, but I'll start by quoting Noonan again:):
" . . . . even a single-decoction (or step) mash is never advisable with British ale or brewer's malts that have been thoroughly modified during malting and would be "over-modified" by exposure to low temperature rests."
Click to expand...
I wonder if Noonan is refering to acid rest or protein rest, or both? I can see this being true with the protein rest, but what do you think about acid rest temperatures? I thought that acid rest temperatures stabilized the mash before saccrification.
 
AnOldUR said:
I wonder if Noonan is refering to acid rest or protein rest, or both? I can see this being true with the protein rest, but what do you think about acid rest temperatures? I thought that acid rest temperatures stabilized the mash before saccrification.
Click to expand...

He doesn't say or even make any implications about it. I don't see how it would be harmful. He does talk about protein rests and soluble nitrogen ratios of the malt. Essentially, malts with a high SNR should get a protein/saccharification rest at 131dF vs 122dF for a low SNR. But he mentions specific numbers in reference to SNR and I think virtually all Marris Otter has a higher SNR than any numbers he mentions, which is why they don't need protein rests. So, he's probably just talking about protein rests.
 
Keith. Thanks for the information. Which Noonan book are you referencing? Just did a search at Amazon and see he has a few. The one you're quoting from is something I'd like to read.
 
AnOldUR said:
Keith. Thanks for the information. Which Noonan book are you referencing? Just did a search at Amazon and see he has a few. The one you're quoting from is something I'd like to read.
Click to expand...

No problem! New Brewing Lager Beer (the "New" means it's not just for lagers anymore). It is packed with understandable technical info that helps you to really understand brewing instead of just going through the motions. Highly recommended.
 

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