-glucanase rest

Hi,

I understand that this rest will help beak down cell walls and make the starches more available for conversion. What I don't understand is how long can the grain can safely remain at this temperature (40C). Also, is there that much of an advantage by doing this rest?

Thanks for any help you can give.

Trip

I did one the last time I brewed. Approx 30 minutes and I used that time to test and adjust PH. I think I got better efficiency but due to a dumb mistake I wasn't able to properly measure my volumes correctly. Basically I hit my gravity numbers but dumped an unknown quantity down the sink -duh!

Most brewers say that the highly modified malts we use today don't benefit from this rest and from a science point I have no way to argue with it.

I do not know exactly how long you can hold this rest for? But this is a quote I found during my reading.


“The grist may be mashed in with cold water and the temperature is raised to
35ÿ40 ëC (95ÿ104 ëF) either by adding hot water, or by direct heating, while the mash is
stirred. The main mash may be allowed to remain at this temperature for about two hours.
During this stand heat-labile enzymes, such as _-glucanase, maltase, proteases and
phytase, have a chance to act.”


In this part of the book the author is talking about doing this is with poorly modified malts.


There is enough evidence now to show that these steps are no longer required. But I know some award winning brewers that still practice at least one step, at 40C. One of them admits it probably does not do much for the beer, but (like samc) he can adjust Ph during this rest and make sure the grain is fully saturated with water to allow hydrolysis of starch, Once he hits saccrification temperature the enzymes are ready to do their work, and you get full conversion easier according to him. He also does this with lagers and ales, but only rest at that temperature for 30 minutes.

Moral of the story, about 2 hours is tops for this temperature.

I've heard from a number of folks that it helps prevent a stuck sparge when using a high percentage of wheat or flaked adjuncts. I've never used it myself, though, so I don't know how true that is.

I can tell you I just did a 70/30 wheat-barley heff and my first rest was at 111 for the acid, and 122 for the protein rest, decocted and didn't get a stuck sparge or lauder at all. Almost every book that I have read doing the decoction for well modified malts do this schedule:

acid rest at 100 for about 10min decoct to 131, decoct to 158

I did the other option due to the wheat percentage:
acid rest 111, infuse to 122, decoct to 145, decoct to 158

Ignore the protein rests with the decoct. With such modified malts, it will adversely affect head retention and mouth feel. At least this is what Noonan clames.

In regard to protein, if the malt you're using has a kolbach index (soluble to total protein) less than 40, it can help to do a protein rest around 56C for 15 minutes. That temp will break up the longer chain proteins that will cause haze but not the medium length chains that aid in a fully body and foam stability.

I appreciate you all chiming in on this issue and with the expediency of your reply. To clarify, I am preparing for a Paulaner Hefeweizen clone batch (~60/40 wheat-barley) for Christmas and wanted to get a better understand the mash process. I had done some investigation on both Paulaner and Franzikaner Hefeweizen (which I really like both) and both talk about a step mash process. You all have convinced me that both an acid and protein rest would probably be the way to go. I will be using all German wheat and modified grains for this batch.

I don’t have any experience with decoction mashing and I don’t want to introduce an unknown at this point so I will step infuse the mash. So if I can guess on a step process, and please correct me if I am wrong, the steps that I should use are:

Acid - 111 for @20min
Protein - 122 - @20min
Sacc - 152 - @40 min
Mash Out - 168 - @10min
Boil - 60min


How does this look?

Thanks again,

Trip

That looks like a very traditional mash step process. Can you heat up the mash tun? I would be hesitant to do infusion mashing with so many steps given the huge amount of water that you would require. That will alter the ph quite a lot. If you can heat up your tun I would say that looks perfect, if you can't, I would definitely learn decoction.

I could use my boiler (10gal) and can heat the mash as I go but I had trouble in the past string to equalize the temperature throughout the mash (false bottom, run out tube, temperature gauge). It is much easier to equalize the temperature in my Igloo tun adding water.

Hmmm... it looks like I am at a delima; learn decoction or risk PH imbalance.

I'll have to think about this one.

Anyway, thanks a bunch for all of your great info. This has helped me a lot.

Trip

You can also start off with a very thick mash, and work your way up from there. But that many steps might still involve to much water. Decoction mashing isn't so hard, I have done it with my 1 gallon test batches. I followed brewing TV's simple directions.



edit:
Kaiser also made an awesome video.

GodsStepBrother said:

But I know some award winning brewers that still practice at least one step, at 40C. One of them admits it probably does not do much for the beer, but (like samc) he can adjust Ph during this rest and make sure the grain is fully saturated with water to allow hydrolysis of starch

Click to expand...

I always mash-in at 100 -104°F to adjust the mash pH and for enzyme prep regardless of how the malt is modified.
I am old school


Cheers,
ClaudiusB

Basically the trick I have found (I have only done it twice) pull a very thick mash with a strainer to get as much grain out as possible but pour on some of the liquid to just above the grain to prevent scorching.

I would follow something like my schedule for the mash, but at the very most only do a double decoction without a protein rest. Infuse 1qt/pound to 111 and 1qt/pound to 122-131. Then decoct to first sac rest at about 145-148 if only at 122 or 158 if you infuse to 131. The 131-158 is the single decoction mash. For both pull about 40-50% of the actual volume of the mash. You can always add cold water to cool it off. I have done this now 3 times and under hit this temp and had to infuse water because I used only about 30%. From there, add the boiling decoction back and let it sit for about 20 miin. Then pull a second thick mash at about 40% and bring it to a boil to hit about 158.

If you think about this like infusion mashing, it's like you are adding boiling liquid (because you are) but it's "liquid" that you took from the mash.

Ok, this Decoction process is pretty interesting. You guys have got me all excited and my brewing juices flowing red hot. Those videos made a lot of sense and I thank you for posting those.

After reading up on Decoction a little I am starting to thing it is similar to the simple step mash infusion process I was thinking about. My guess is that instead of just adding boiling water for reach each rest, you simply add the same amount of boiling mash back to the original mash to raise the mash temperature to the next rest.

Am I thinking correctly about this? It can’t that simple, is it?

For example:
From an acid rest of 111degF, I have calculated that it would take 1.4qtr of water at 212degF to raise the mash temp to 122degF. I got that from Brewers Friend Beer Batch Stat Calculators.

So for a Decoction process, would it take the same 1.4qtr of the mash heated to 212degF and added back to the original mash to raise the temp to 122degF?

If this is correct, I can do this!

Please let me know if I am half cocked with this or not...

Thanks,
Trip.

the percetange of volume that you need is:

t_target-t_start
---------------------- = % volume of mash
t_boil - t_start

If you want to go from 72 to 112 you will have:
112 - 72
------------ = 40/140 = .28.
212- 72

You really want to pull plus 30% or more so about 36% of the total volume of the mash. I can't remember the formula to calculate the mash volume but you can find that formula on line. Basically you want to pull about 40% almost all of the time. The thing is though, you can dough in at 122 or 111 with warm water. Let it sit 10min and then pull about 40% of the mash volume. This is very different from the liquor volume because the grain absorbs water. Have boiling water on hand in case you miss the temp, but you can always add cold water to cool off the mash. It takes a lot of practice, I have done it 3 times and I am starting to get it, but the flavor can not be matched.

Also if you do this, plan on VERY high efficiency. I hit somewhere between 95-99%

Just remember that it will take some time to pull the decoction, convert it, heat it up to a boil without scorching, and boil it for x minutes. It might be longer than you want to rest at, say the protein rest temp. Also, it will take a fairly large decoction to go from 122* F up to a sacc rest temperature (which also means more time needed to heat/boil the decoction). And when you pull the decoction, the total volume in your mash tun has been reduced by that amount. So the volumes aren't quite the same as if you were just adding an infusion to the 'full' mash volume.

AH... % volume of mash, that is what I missed. Thanks asterix404 for making that clear. Now it makes more sense and according to the video from Kaiser he mentions a 20% fudge factor to the amount pulled from the mash. So to follow the formula, 20% of .28 would be .336 or 20% of .30 is .36. IMO, this makes the decoction process simpler than what I was making it out to be.

Ok, so this brings up another question: For the mash that remains after you pull the decoction, is it important to keep that at the rested temp until you add back the boiled decoction amount? That wasn't very clear in the videos.

I would think so because it could take some time to get the decoction amount to boil without scorching (as asterix404 and SpanishCastleAle mentioned) and I would think you would not want the original mash to cool to much because you might not hit your next rest temp target, right? However I suppose like you guys said, you could add a little boiling water, or cold water for that matter, to your mash and not greatly affect the PH to much.

Well, I am sure that when you get right into the process decoction is more complicated than I am making it out to be. But I certainly feel much more educated in the process now than I did yesterday.

I am going to review the videos again and read more on decoction and try decoction on my Paulaner clone this weekend. At least I feel like I checked to make sure there was a safety net before jumping off the cliff...

Trip

Yes, the mash tun should remain at a constant temperature but hopefully you have a system which will reduce temp by about a degree an hour. Each pull will take about an hour. This will increase your brew day, but the results can not be matched.

It's a lot of planning until you really get use to the process and I had to read and compare about 5 books to get a decent result from the first time I did it. The best was combining information from various books since every author seems to have their own decoction mash schedule. Basically, we don't use BADLY under modified malts, so we don't have to do a triple decoction. We are doing it for flavor and even decocting one time will significantly increase efficiency (which was the initial reason for doing it in the first place). In fact a triple decoction will most likely cause more problems then it's worth. The most I would ever consider doing is 2. The reason is that the badly under modified malt had a huge protein content and needed to be broken down quite a lot. Also malting didn't really generate a lot of simple sugar, so the triple decoction was used to extract quite a lot of the carbohydrates from the malt. Also the boiling would break down the carbohydrates in the malt and the enzymes remained in the liquid in the mash tun. So basically, when you poured it back, the enzymes were working very effectively with REALLY terrible malt. Protein is no longer a problem so resting the decotion at the protein rest breaks down so much more then is helpful.

Good luck, and there is a huge amount of fudge factor available here, so really don't worry too much about hitting temps without adding water at first. You and I will get there together but I have a feeling that this whole process was developed without quite a lot of trial and error.

Cool. I was thinking of doing the original dough-in at 122degF using my Igloo 10gl tun vs. the boiling pot. That tun is quite good at keeping the temperature constant for long periods of time. And I will certainly keep a pot of boiling water handy just in case I need to add a little to hit the numbers.

I want to thank you guys for all the help you shared. I will certainly update this post with what occurred this weekend. I asked my buddy Chris to join me on brew day so I won't be traveling down this journey alone. Either we will be celebrating or drowning our sorrows with some of our previous brews. What ever happens, it will be a great day. Hopefully, with a little wing and a prayer, I will get through my first attempt without getting to scorched...no pun intended

Trip

ClaudiusB said:

I always mash-in at 100 -104°F to adjust the mash pH and for enzyme prep regardless of how the malt is modified.
I am old school


Cheers,
ClaudiusB

Click to expand...

TripHops said:

Cool. I was thinking of doing the original dough-in at 122degF using my Igloo 10gl tun vs. the boiling pot. That tun is quite good at keeping the temperature constant for long periods of time. And I will certainly keep a pot of boiling water handy just in case I need to add a little to hit the numbers.

I want to thank you guys for all the help you shared. I will certainly update this post with what occurred this weekend. I asked my buddy Chris to join me on brew day so I won't be traveling down this journey alone. Either we will be celebrating or drowning our sorrows with some of our previous brews. What ever happens, it will be a great day. Hopefully, with a little wing and a prayer, I will get through my first attempt without getting to scorched...no pun intended

Trip

Click to expand...

Sorry I couldn't get online for a while. Hope all goes well and keep us updated!

Well.. my buddy Chris had to do gardening chores with his wife this weekend, so I am going to postpone our Paulaner brew for another weekend. I am sure he was really happy about that getting his hand dirty with dirt vs. grans...

Anyway, I did some hefeweisen this weekend and saved the Paulaner grains for when Chris can get free.

Trip

Hello Again,

Well, my friend Chris and I finally got to brew our Paulaner clone this past weekend. Since I was a little chicken to use a full double decoction we used a infusion to sacc from protein and decoction to mash out. I am glad we did that because we missed out mash out temperature.

Anyway, here is a brief on how it went. We started out with almost 11lb grains comprised of German Wheat malt (6lb), German Pils (4lb), Munich (3/4 lb), Caramunich (2oz) and Carafa II (1oz). We did the protein rest at 127degF for 20min with 1.25qtr/lb. I did a PH test at the protein rest and the reading was 5.42. After 20min we infused 212degF water to raise the mash to 153degF for 45min which brought it to 1.8qtr/lb. We hit that temperature exactly. Unfortunately I didn’t do a PH test at Sacc rest, which I should have because I think the PH might have been a little higher. Next time I will do a second PH test and adjust if necessary or simply decoct from protein to sacc rest.

After 45min of Sacc rest, we decocted approx. 29% of mainly liquid from the mast and brought it slowly to a boil while constantly stiring. I have to admit, it smelled really good after a 15min boil. We kept the mash tun shut to maintain the original 153defF temperature. Unfortunately, when we put the decocted amount back into the mash, it only raised the temperature of the mash to 162degF. We missed our 170degF target by 8degF. We certainly need to make an adjustment on the amount decocted in the future. I am sure glad we decocted for Mash out instead of the Sacc rest and found out we would be short. At least the mash out is somewhat optional and I think we should be OK.

So...I am wondering where I went wrong to miss our mash out temp by 8degF. Obviously I didn’t pull enough from the mash. I used the decoction formula of:

t_target - t_start
----------------------
t_boil - t_start

170-153/212-153 = 17/59 = 28.81%

So if I had to pull out more than 29% this formula is not indicating that. Is there some constant that I was missing?

The wort is fermenting vigorously but it is a little darker than anticipated. It seems that it will finish closer to a Dunkle. My guess it is from the Carafa II or Caramunich. I might cut down a little on those next time.

I hope I gave enough detail above. Any suggestions on how I missed that mash out mark would be greatly appreciated.

Trip

Looks like a problem with the formula. The heat gained by the rest mash, m_r*(T_target - T_start) must equal the heat lost by the decoction, m_d*(T_boil - T_target). Thus the ratio of decoction mash to rest mash must be m_d/m_r = (T_target - T_start)/(T_boil - T_target).

Thanks for your reply ajdelange. However, I am at a loss what you mean when you say "must equal the heat lost by the decoction" and those two variables; m_r and m_d. Can you give a little more detail about those variables?

thanks,
Trip

Well, since this Post I have completed 3 decoction attempts. Each time I am getting closer to my target numbers but still a slight bit short. I reviewed some more videos and read a lot about decoction mashing and there are a couple of things I have observed that aren’t really mentioned or are mentioned in a way that is somewhat vague or I simply didn’t pick them up.

Since I do my decoction mashing in a non-fired mash tun, it is a bit more interesting than on a fired mash tun. One of the important items I am finding out is that you need to know your exact mash volume. This is the volume after you have added your first rest target water then the grains. With that measurement I feel you can get a much better decoct percentage to remove from the original mash.

On my last batched I infused the 10.4lbs of grains in 13qts @ 124degF water but didn’t get a good measurement of the total mash volume. I only measured the inches from the bottom of the tun to get an idea where the 1/3 measurement would be. I decocted a little more than 1/3 of the thick mash, rested at 152degF for 20 min (starch test was good) and raised to 212degF. I had to add all the decocted amount to the original mash (which was still at 124degF) but the original mash only came up to 147degF. So, my guess is that you need to remove somewhere between 40 - 45% of the thick mash vs. 33 - 35% to hit your Saac target.

Another thing I noticed is that once your decocted amount comes to a boil for 10 min most posts and videos have you remove the pot from the flames. I notice that by the time I add the last of the decocted amount to the original mash, the temperature of the decocted mash has dropped to below 180degF. This could also be why I have been short on my target numbers. I am thinking that you need to keep the decocted amount boiling or close to boiling until you add it all back or add enough to hit your target rest temperature then take it off the burner.

Anyway, I thought I would pass these two observations along.

Trip

TripHops said:

Thanks for your reply ajdelange. However, I am at a loss what you mean when you say "must equal the heat lost by the decoction" and those two variables; m_r and m_d. Can you give a little more detail about those variables?

Click to expand...

Sorry it took me so long to respond. I only noticed this post when I got alerted about your last post.

Heat is conserved. Thus any heat that flows into the rest mash mass must come from the decoction mash mass. The heat lost or gained by a mass is the thermal mass of the mass (which is the physical mass multiplied by the specific heat) times the temperature change of that mass. m_r is the "thermal mass" of the rest mash and m_d is the thermal mass of the decoction. Since the specific heat is approximately the same (approximately because of the thickness differences between the rest mash and the decoctions) the ratios of the thermal masses and the plain old garden variety masses are approximately the same. Thus, for example, if you want to raise the rest mash from a protein rest at 125 to a saccharification rest at 150, a raise of 25 degrees then the decoction temperature would drop from 212 °F to 150 °F for a drop 62 °F then the ratio of the decoction mass to the rest mash would be 25/62. This condition would be met if the decoction were 25 pounds and the rest mash 62 pounds thus the decoction should be 25/(25 + 62) = 28.7% of the total mash mass.

This is, of course, an approximation which does not take into account things like mass losses from evaporation or mass gains from temperature maintenance infusions and losses of heat from the decoction or rest mash through the walls of the tuns or during transfer.

So the rule that I almost always follow is this:

Use that formula and pull out about 10% more than you think you need to, this ends up being almost always about 40-50% of the mash VOLUME. If you have 5g of mash, you need to pull out a thick decoction of about 2.5g. At this point I love the fact that my cooler has a volume measurement built right in. I will have to read more of this topic by people who know much more than myself, but basically... I take out 50% and if I see that I need to lower the temp I can add a bit of cold water. Very little goes a very long way.

Formulas are fine but I, in practice, do essentially what you do. In my case I need to pull enough of a decoction to cover the steam coil in my decoction vessel (guess I don't really need to but I don't want stuff baking on to un-submerged parts of the coil) which is generally more than the formula dictates. I too adjust with cold water. This effectively makes up for the water lost during the decoction boil which is a 15 - 20 minute vigorous boil. With today's well modified malts the only reason for doing decoctions is to get melanoidins and the longer you boil the more melanoidins you get.

From my past attempts, I agree with your guys. I was treating a formula as finite when in fact it is simply a guideline and only with experience can you attain your target temps. I am sure glad I got into the decoction method. It makes a lot of sense for improved head retention and mouth feel especially for the Bavarian weizenbier I am brewing.

Thanks you guys for all the help and guidance.

Trip