Single Decoction Question

[periwinkle1239]

I'm planning to try a single decoction for a doppelbock kit from NB. I noticed the NB instructions list both a 30-min beta (149 F) and a 30-min alpha (158 F) sach rest.

Based on this Decoction mash - Home Brewing Wiki my understanding is that a single decoction only has one long sach rest between 149 -158. So what temperature should I do this rest at?

Or, should I try to do two shorter sach rests like NB lists?

My plan is to do the decoction to reach the mashout temp.

I appreciate the help. I've done a few single infusion mashes and feel like those are simple and want something a little more challenging. I believe I can do it without the need to purchase more equipment (which is a plus!). This will be my first decoction if I try it and it sounds like a good idea for the lager (doppelbock) I'll be brewing.

 

[TimT]

This what the two sach rests do and are
Decoction Mashing - German brewing and more

 

[hamiltont]

I've had my best luck with a modified Hochkurz-like Double Decoction by eliminating the protein rest and mashing in at ~145F, after 30 minutes pull a thick decoction and raise it to ~158F & hold for 20 minutes and then bring to a boil. Add the thick decoction back to the mash for a target mash temp of 158F. After 20 minutes pull a thin decoction (just runnings & no grain, or you could pull another thick decoction it you want) and bring it to a boil, add back to the mash for a mash out of ~168. It will add a lot of time to the process but it's not rocket science. Your mash tun efficiency will increase quite a bit with a decoction. Mine has gone up as much as 10% on occasion so keep that in mind when designing the beer. Cheers, and Happy Decocting!!!

 

[periwinkle1239]

I've had my best luck with a modified Hochkurz-like Double Decoction by eliminating the protein rest and mashing in at ~145F, after 30 minutes pull a thick decoction and raise it to ~158F & hold for 20 minutes and then bring to a boil. Add the thick decoction back to the mash for a target mash temp of 158F. After 20 minutes pull a thin decoction (just runnings & no grain, or you could pull another thick decoction it you want) and bring it to a boil, add back to the mash for a mash out of ~168. It will add a lot of time to the process but it's not rocket science. Your mash tun efficiency will increase quite a bit with a decoction. Mine has gone up as much as 10% on occasion so keep that in mind when designing the beer. Cheers, and Happy Decocting!!!

That's great, I like it. I may try this. A few more questions:

What water/grain ratio do you use for your mashin?

How thick is your decoction? Maybe half of your mashin volume? Do you just eyeball it? I'm assuming you are stirring quite a bit while heating to avoid scorching the grains.

 

[hamiltont]

Answers below in bold.

That's great, I like it. I may try this. A few more questions:

What water/grain ratio do you use for your mashin? 1.5:1

How thick is your decoction? Thick like a bowl of oatmeal. I use a large strainer to get the grains & a pitcher for some wort. You can always add more wort if it gets too thick. You'll get the feel for it when you get going.

Maybe half of your mashin volume? I eyeball it but usually 30-40% of the grain volume is decocted. If you hit your next temp when adding it back to the tun just stir the decoction to cool it down & add it to the tun when it's at the temp. If you add it all back & you're temp is still under just add some boiling water to the tun. I usually have a couple gallons of the sparge water boiling just for that reason.

Do you just eyeball it? For the most part yes.

I'm assuming you are stirring quite a bit while heating to avoid scorching the grains. Definitely! The only time I'm not stirring the decoction is when it's resting. A towel around the pot helps insulate it a bit during the rest.

 

[periwinkle1239]

There is one question I didn't ask about. Since my MLT equipment is for batch-sparging with a cooler, I'm assuming I should plan on sparging at 170 degrees after I complete the mashout to rinse the grains? Or is rinsing the grains like you do in a batch-sparge not necessary since the mashout is at 168 degrees?

This might be a stupid question. But I hope I'm making sense, I'm new to AG and still trying to get the terminology down.

 

[asterix404]

So I can almost guarantee that your recipe calls for an infusion to 149 and a sac rest at 158. The decoction brings the mash to158 from the initial infusion of 149. Multiple decoctions are great too and will never harm your beer.

You want a thick decoction, just enough liquid so that you can stir the grain and it won't scorch on the bottom. Low heat is always your friend, I do mine on a stove top and boil on the out door burner.

You always want to pull all of the grain. If you get a hotter temp, adding cold water is always an option. Adding boiling water is a huge pain. I always do a 50% volume pull.

Typically I start out with 1.5qt/lb water to grain but between 1.5 and 2qt/lb is great. remember that you will be boiling off water. I typically do whatever the nearest half gallon or gallon is. for instance I am going to a beer with 10lb of grain at 1.5qt/lb, this is 15qt, I am going to use 4G of water. You don't have to do this and you can be as exact as you want, but I prefer this method because I can easily keep track of how much water I add. To each their own.

The mash out temp of 168-172 will stop all enzyme activity and is generally not needed. It does dissolve the sugar more though. You do want to rinse or "sparge" your grain with water to get the grain bed up to 168-172 without really going over 172. Some will say that even 172 will leach tannins... I don't think it does or I haven't noticed it. You sparge to get even more sugar out of the grain. Also you stop enzyme activity but really the reason is to wash all of that precious sugar off of the grain and get it into your kettle. There is also a no-sparge method which is exactly what it sounds like.

A fun activity is actually to take the first runnings from the mash and keep them aside and then drain the first sparge to get a session beer. This is typically done with larger batches, like an imperial IPA with 16lb of grain and a more normal IPA with the first runnings possibly in the high 80's and the next running being in the low 40's.

 

[osagedr]

I've had my best luck with a modified Hochkurz-like Double Decoction by eliminating the protein rest and mashing in at ~145F, after 30 minutes pull a thick decoction and raise it to ~158F & hold for 20 minutes and then bring to a boil. Add the thick decoction back to the mash for a target mash temp of 158F. After 20 minutes pull a thin decoction (just runnings & no grain, or you could pull another thick decoction it you want) and bring it to a boil, add back to the mash for a mash out of ~168. It will add a lot of time to the process but it's not rocket science. Your mash tun efficiency will increase quite a bit with a decoction. Mine has gone up as much as 10% on occasion so keep that in mind when designing the beer. Cheers, and Happy Decocting!!!

I've done something similar to this for my bocks. My rests would be a little longer but the idea is the same. Three hours or more for a mash is not uncommon at all.

To the OP, learning to decoct with a single decoction for mashout is safe b/c everything is converted by the time you boil your decoction. When you start getting into more decoctions, you have to rest your decoction in the conversion range for a bit before taking it SLOWLY to a boil.

 

[periwinkle1239]

Just got done with my day of decoction for a doppelbock. What a day it was. I basically used the modified double decoction on this thread, thanks for the post!

My efficiency turned out really good, the recipe kit called for an OG 1.083 and I was in at 1.080. I pitched my huge starter (decanted). Although it was a great day I'm so exhausted that I don't know if I'll do another decoction ever again...well let's see how the beer turns out first .

 

[Yooper]

Just got done with my day of decoction for a doppelbock. What a day it was. I basically used the modified double decoction on this thread, thanks for the post!

My efficiency turned out really good, the recipe kit called for an OG 1.083 and I was in at 1.080. I pitched my huge starter (decanted). Although it was a great day I'm so exhausted that I don't know if I'll do another decoction ever again...well let's see how the beer turns out first .

Oh, you will! Trust me. I do decoctions on all traditional German lagers, and I try to geek out totally on the day I do them. It's just one more thing in your brewing arsenal, and when you sip the beer you made you'll be even more appreciative of the techniques. I don't make many lagers, so when I do I feel like I want to spend the whole day doing things I normally don't.