Dough-in speed. FG Thin mashes and fine-milling. Any correlation?

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Gavin C

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In a recent (and current) thread by @Brew_G , myself and other members were scratching our heads in an effort to utterly confuse :) the OP with ideas as to why his beer finished at somewhat higher specific gravity than planned

The usual suspects were touched upon and include of course

  • Mash temperatures
  • Accuracy of thermometer used to determine mash temps
  • Oxygenation of the wort
  • Recipe and percentage of specialty malts
  • Yeast management and pitch rate

One thing I added was dough-in speed and stike temperature. @Islandlizard mentioned this would be worth discussing in a thread so hence this post. This is taken verbatim from that thread


____________________________


I think a culprit in BIAB with thin mashes and fine milling is slow dough-in. Conversion is so rapid that if you're too slow it may impact the FG. I have no good data or citations to add to this thinking. Possibly nonsense.

I've been step mashing starting at 130-144F for a first step and going up from there. Doughing in in under 1 minute. As apposed to striking high and coming down. I'm striking in the protein rest or beta amylase range and coming up either with direct firing the tun and stirring (important) or adding infusions.

It's very simple and under utilized with BIAB IMO. Step mashing can in theory add complexity to the mouthfeel and head retention of the beer. Again, not very well versed in the science so a pinch of salt warranted.

If you enjoy a bit of complexity, have the time and a good thermometer, this could be something to consider for a future brew.

This morning's mash. Protein rest, infusion to beta rest, decoction to alpha, direct heating to mash-out
attachment.php


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My question is in a nutshell as follows.

What are other peoples thoughts on this dough-in issue? Is it utter nonsense or does the idea have any merit? Is anyone else doing things in a similar manner and if so why?

The thoughts and ideas from the HBT think-tank would be most welcome.
 
I think it's quite probably given the recent discussions on our quick conversion times, and I was having a bit of an issue with my strike and starting mash temp yesterday (80 schillings scottish ale) when I put my wet (read:cold) biab bag into the brew kettle it lowered the strike temp almost 10 degrees, so I re-heated it stirring often, and overshot by about 2 degrees.

Doughed in anyways because I'm impatient, and ended up with a starting mash temp of 160.5-161 instead of 158~. I added about a cup and a half of cold tap water (1.1G batch so didn't need too much) and brought it down to 156 so I didn't have to worry. Brought it back up with some heat on low, and lots of stirring.

Anyways, I'm contemplating doing something similar to you on my next batch with a high mash temp, so I don't have to worry about denaturing any enzymes with such a high temp. IIRC, @owly005 does a similar method where he does an "inline" mash is what he refereed to it as. However I probably won't worry about it unless my mash temp is supposed to be over 155.

I also dumped all the grains in at once and just stirred it out, no dough balls. Took about a minute or two.
 
As I understand it %80 of the conversion takes place in the first %20 of a 60 min mashing and tails off exponentially, so you need to dial-in your temp within the first 3 to 4 min. Is this correct?
 
This is an interesting theory to me because more often than not my FG is lower than anticipated. And from what I've read, it seems that a lower FG is something that plagues more BIABers than a high FG.

So I guess what I'm trying to say is that my experience has been the opposite with a 0.025 gap and strike temps 6-8 degrees higher than mash temp.

Edit: like Priceless, I also put all my grains in a bag and just submerge it all at once, working out the dough balls afterwards. Also, maybe I'll try out the protein rest this weekend.
 
I doubt I'll ever do a protein rest, but I might mash in around 148 and let it sit for 5 minutes then slowly raise the temp to my desired mash temp.
 
As I understand it %80 of the conversion takes place in the first %20 of a 60 min mashing and tails off exponentially, so you need to dial-in your temp within the first 3 to 4 min. Is this correct?

I'm not sure on the numbers or exact timings but this is indeed my thinking. Particularly after reading some of @RM-MN 's experiment threads on very short mash times.
 
This is interesting, and I think it is a possible factor. Though I don't do many step mashes (actually only one so far), and I usually do single infusion BIAB, I still think this could be an issue.

I have been doing a gradual dough-in process: pour in a couple pounds of grain, stir, pour in some more, etc. This takes about 3 or 4 minutes, a span of time which might be a significant chunk of the overall conversion time. Thus, it's possible that the first portion of the grain is mashing high while the water is still hot, and later additions of grain mashing progressivley lower, as the mash temp is dropping as I go.

If, for example, I'm shooting for a mash temp of 152, it's possible that a significant portion of my grain on the front end of dough-in is mashing at, perhaps 156. I tend to get higher than expected FGs. Since I am diligent to provide good oxygenation, pitch adequate amounts of yeast, etc., maybe this is something I need to consider.

Next brew, I might try the "Priceless Method." Fill the bag completely, drop it in and stir like crazy. That way, most of the grain will have nearly instantaneous contact with the strike water.
 
Next brew, I might try the "Priceless Method." Fill the bag completely, drop it in and stir like crazy. That way, most of the grain will have nearly instantaneous contact with the strike water.

I place the bag in the pot when the water is cold heat it to strike, stir ensuring uniform and true temperatures are in effect and tip the grain in from the bucket over a 1 minute span.

As a variant to the priceless method (make sure you get a patent on that one @pricelessbrewing) ,last brew (the mash profile I illustrated), I dumped the grain from the bucket into the water in 1-2 seconds. No dough balls after a minute of stirring.

Homogenous wort at target temp achieved. Same as usual.

What you are descibing @Maxstout sounds very system to the method I used to employ and was seeing a few beers where the FG was a couple of points higher than I wanted. That's why a changed some time back. True, not the best of evidence but interesting to hear the similarities in process. Thanks for that.
 
I'm having a hard time thinking of a reason that slow dough in would reduce mash fermentability. Given enough time (at temps that won't denature it) alpha amylase will produce a very fermentable wort. It's just not as efficient at that as beta amylase. In a thin, fine crush mash with high saccharification rates, both beta & alpha get more "effective" time (where effective time = rate * time) to work so that higher fermentability should be the norm for equal mash times vs. a thick, coarse crush mash. Only thing that makes sense to me is strike/mash temps high enough to denature much quicker than normal.

Brew on :mug:
 
I have put bag/basket in cold water grain in bag/basket in cold water and heated it up to mash temp did not notice any ill effects. As a matter a fact it was the best batch I have made to date.10% Citra IPA
 
I'm having a hard time thinking of a reason that slow dough in would reduce mash fermentability. Given enough time (at temps that won't denature it) alpha amylase will produce a very fermentable wort.

Brew on :mug:

Yup, that's why I plan on doing it on the next time I have to mash 156-158. Just to help avoid that potential problem area, dough in using the innovative Priceless method* for 152-154 then apply gentle heat while stirring.

*The Priceless method is a trademark of Priceless Brewing, patent pending.
 
Yup, that's why I plan on doing it on the next time I have to mash 156-158. Just to help avoid that potential problem area, dough in using the innovative Priceless method* for 152-154 then apply gentle heat while stirring.

*The Priceless method is a trademark of Priceless Brewing, patent pending.

This sounds like what Sabco recommends with their BrewMagic system. Dough in with your water at your mash temps and then raise the mash back up to that temp once it's "settled" for 10 minutes.

So for me, if my mash temp is 154F, I set the target temperature on my Tower of Power to 154F. Once that temp is reached, I turn off the pump and dough in. The temp drops a bit of course. I let the mash settle for 5 minutes or so. Then I turn the pump back on and let the system bring the temp back up to 154F. Once it's at that temp, only then do I start my "mash timer." It's worked well because I know with absolute certainty that I will NEVER denature any of the enzymes that I'm wanting to go to work. :)
 
Since I mash in a cooler I work my way "down" from strike temp to mash temp and hope it holds steady. I cover my cooler w/ about 4 padded flannel shirts. LOL
 
This is an interesting theory to me because more often than not my FG is lower than anticipated. And from what I've read, it seems that a lower FG is something that plagues more BIABers than a high FG.

So I guess what I'm trying to say is that my experience has been the opposite with a 0.025 gap and strike temps 6-8 degrees higher than mash temp.

Edit: like Priceless, I also put all my grains in a bag and just submerge it all at once, working out the dough balls afterwards. Also, maybe I'll try out the protein rest this weekend.

My FG's seem to have dropped since I started doughing in faster. When I started I poured the grain in slowly as I stirred and I got lower conversion efficiency and higher FG's. Now I pour all the grain in at once and spend about a minute stirring and mashing doughballs, and my efficiency is much higher and my FG's tend to be lower. There are certainly some mitigating circumstances there including better temp control and a couple infected batches skewing the numbers, but that's where I'm at. I use a tight gap on my corona mill and ferment most beers up to ~1.060 with a single packet of dry yeast, no rehydrating, anything bigger gets two packets.
 
My FG's seem to have dropped since I started doughing in faster. When I started I poured the grain in slowly as I stirred and I got lower conversion efficiency and higher FG's. Now I pour all the grain in at once and spend about a minute stirring and mashing doughballs, and my efficiency is much higher and my FG's tend to be lower. There are certainly some mitigating circumstances there including better temp control and a couple infected batches skewing the numbers, but that's where I'm at. I use a tight gap on my corona mill and ferment most beers up to ~1.060 with a single packet of dry yeast, no rehydrating, anything bigger gets two packets.

How's this for a theory to explain your observations: A fast mash in drops the temperature of the strike water faster, as the temperature lowering grain gets into the mix quicker. The shorter time above target mash temp denatures less of the beta amylase, so the higher concentrations of beta amylase can work to provide a more fermentable wort?

Brew on :mug:
 
How's this for a theory to explain your observations: A fast mash in drops the temperature of the strike water faster, as the temperature lowering grain gets into the mix quicker. The shorter time above target mash temp denatures less of the beta amylase, so the higher concentrations of beta amylase can work to provide a more fermentable wort?

Brew on :mug:

This is exactly what I am theorizing in my OP. Get the full body of the heat sink into the strike as fast as possible and temperatures will drop faster getting your mash in the target temperature faster.

You know that feeling on the family jewels when slooowly lowering oneself into a hot bath. After a minute or so things have cooled as the body is fully immersed. The jewels are no longer subjected to the hotter temps. A very bad comparison I know for a variety of physical and subjective reasons but similar at least to a point. Maybe not..:)
 
One thing that I've liked about full volume mashes is that the strike water is so much closer to the mash temperature. With Strike Water Temperatures around 160F, I am a lot less worried about denaturing my enzymes as compared to a more traditional mash using 1.25qt/pound. Back then I was adding grain to 170F strike water and hoping that the enzymes would stay alive long enough to survive the temperature drop.

But from what I hear, denaturing enzymes is a process that occurs over time. The hotter they are, the more quickly they denature. It is almost like they have a half life based on the temperature water they are sitting in.

For me, I only do single infusions. If the FG is too low, I'll increase the mash temp next time and vice versa.

It is interesting to hear the thought that goes into this and seeing the results of tests you all are doing.
 
...
But from what I hear, denaturing enzymes is a process that occurs over time. The hotter they are, the more quickly they denature. It is almost like they have a half life based on the temperature water they are sitting in.

...

This is correct. They do have a half life depending on temp.

Brew on :mug:
 
Question: Say you want to do a step mash. How long does it take for the beta amylase to convert most of the starch to maltose, say at 130F. Would you have to worry about there not being enough base starch left over once you raise the temp for the alpha amylase to produce dextrose? IF most of the conversion happens in the first 20 minutes, then mashing 30 min at a lower temp and 30 min at higher temp would seem to produce mostly fermentable sugars rather than a half and half ratio.
 
While I don't fine mill I do think adding the grains at different speeds will change the temperature of water differently. MY setup is a Coors Keggle and I typucally add between 8 and 9 gallons of water. After a few experiments it doesn't appear that I lose much temperature after adding grains.

I add my strike water and heat it to my desired mash temperature.
I pour the grains in over what I would guess to be 2-3 minutes while stirring. Sometimes I'll get fed up and just keep pouring and the dry grains will build up and I'll stir them in.
I check for clumps then leave the keggle uncovered and uninsulated for 10 minutes while the enzymes go to work. I'll check the temperature in a couple different places after the first 10 minutes to see where I'm at. I think I'm usually above where I want to be but most of the time 1-2F is close enough.
I've changed from stirring the grain bed every 15-30 minutes and now I just let it sit and keep itself insulated.
I don't attempt to change mash temperatures because when I have using direct heat it has come out bad. Last brew I attempted to bring my grains up to 158 and with the thermometer in my hand in the grain bed and the heat on which isn't the most comfortable places to stand I overshot the temp and hit about 164 halfway into my mash. Thanks to beersmith I added water and chilled it down.
For this specific brew I hit 70% brewhouse efficiency and everything dumped into the fermentor was right at the 5 gallon mark.

I haven't kegged it yet but I'm expecting 4.75 gallons and mostly because I haven't brewed consistently enough because I'm also training for a marathon and after running 15-20 miles (18 today in an hour) I'm not really excited about lifting 15 lbs of soaking grains. I also had a lot of other stuff going on so I'm getting back into it.



At 130F I'd do about 15 minutes. I've seen suggestions of 10 and 20 so I go in the middle for a first attempt. I wouldn't worry about there being an insufficient amount of start for alpha amylase because alpha amylase works at a different portion of the starch molecule. Beta enzymes cut molecules in the middle if I remember science class correctly, and alpha enzymes cut from the outside in so they can cut into individual molecules of glucose instead of chunks/globs/balls/multiple glucose molecules stuck together.

I think a good number of people do exactly what you're discussing. Dough in and do a 120-130F rest for 15, Mash at 147 for 30, mash at 156 for 30 then mash out for 10. I haven't seen too much discussion about it in here but that could be because I don't read too much in here or skim a lot of it. My suggestion would be to make the same beer on the same equipment with as little variation as possible to see how each comes out. It's a major reason I want to get into 10 gallon batches.
 
Question: Say you want to do a step mash. How long does it take for the beta amylase to convert most of the starch to maltose, say at 130F. Would you have to worry about there not being enough base starch left over once you raise the temp for the alpha amylase to produce dextrose? IF most of the conversion happens in the first 20 minutes, then mashing 30 min at a lower temp and 30 min at higher temp would seem to produce mostly fermentable sugars rather than a half and half ratio.

You know, I agree that's a great question...

And related...
Saw a Czech lager recipe (a lighter ABV) that is supposedly really good and used Decoction mashing technique. Won some big awards. I wondered about using a step mash instead, how good would that emulate Decoction mash. Just from conversion standpoint they should work same (yes?). But does bringing portion up to boiling really impart some advantage? Wouldn't that cause the boiled portion of the mash no longer to be able to extract enzymes (???) for ferment ability once cooled back down / added back to the rest of the cooler mash?
 
Wouldn't that cause the boiled portion of the mash no longer to be able to extract enzymes (???) for ferment ability once cooled back down / added back to the rest of the cooler mash?

There are still enough enzymes in the main mash in solution.

So when the decocted grains are added back in the gelatinized starches can be converted to sugars without problem. The grain bill is formulated to ensure that there is enough diastatic power to permit a decoction. A saccharification rest can also be carried out on the decocted portion if desired.

Far from experienced in decoctions but my last brew, a Munich Dunkel with the decoction mash I illustrated earlier had no issues with wort fermentability.

Crashing the wort now after verifying FG at 1.011 (right where I wanted it). OG was 1.053.

Does it taste any good? Time will tell but all seems in order at this stage.

OG and FG.jpg
 
Wow! 18 miles in an hour. That's moving! good luck in the race...awesome and respect!!!


Lol I didn't think before I ran. I was saying 1 hour from posing I would be running 18 miles. It became 15 miles running, 1 mile run/walking and a mile downhill jogging. It took about 3 hours and 10 minutes.
 
Adding all the grain quickly and stirring like mad has gotten me the "best" FG results - not too high and not too low.

I had VERY erratic results with slowly stirring as I slowly added grain. That took an average of 4 minutes, and it led to high or low, but rarely accurate, results.

'Dump it all in and stir like a mad man' is my favorite method now!
 
Sounds like there are a few folks do things similarly for similar reasons. Thanks to all for your helpful replies.
 
Question: Say you want to do a step mash. How long does it take for the beta amylase to convert most of the starch to maltose, say at 130F. Would you have to worry about there not being enough base starch left over once you raise the temp for the alpha amylase to produce dextrose? IF most of the conversion happens in the first 20 minutes, then mashing 30 min at a lower temp and 30 min at higher temp would seem to produce mostly fermentable sugars rather than a half and half ratio.

Great Question. One I have pondered too.

I have no idea how exactly the step mash will impact the actual maltose:dextrine ratio. No clue.

I have wondered if I allowed the beta rest to proceed too long would it negate any benefit of an alpha rest*.

*Apologies in advance for my bad descriptive names of the various rest points.
 
'Dump it all in and stir like a mad man' is my favorite method now!

This is my preferred method as well. I do find it interesting that it still takes considerable time for the mash temp to stabilize. My initial temp readings are around 3-4 degrees above my temp around 5 minutes post grain addition after a second thorough stir.
 
This is my preferred method as well. I do find it interesting that it still takes considerable time for the mash temp to stabilize. My initial temp readings are around 3-4 degrees above my temp around 5 minutes post grain addition after a second thorough stir.

Is it because the temperature hasn't stabilized or is it because conversion is an endothermic reaction and is lowering the temperature? If you stir well would that not get the water and grains to thoroughly mix with a stable temperature?
 
Is it because the temperature hasn't stabilized or is it because conversion is an endothermic reaction and is lowering the temperature? If you stir well would that not get the water and grains to thoroughly mix with a stable temperature?

The grains have a thermal mass, so first it takes a little bit for it to heat up. Secondly the grains take a little bit. Fully saturate and absorb all the water. I would probably peg this mostly done around 3 minutes after dough in in my experience, but I've never really paid too much attention to it and 5 minutes could definitely be a reasonable number.

I'm not sure if conversion is endothermic or not, anyone have a citation on that one?
 
After reading this thread, I decided to go ahead and dough in all at once on my last batch - a Centennial IPA with a 12.5 lb grain bill and a 1.75 gallon sparge brewed 12 days ago. I heated my strike water to about 3 degrees shy of what Priceless Brewing indicated just to see if I'd hit my mash temps with the quick dough in.

Negative, Ghostrider.

I came in a couple degrees short on mash temp. I attribute this to having to stir pretty vigorously for a few minutes to get rid of doughballs. So I hit the burner and brought temp up to my planned temp of 150F within less than a minute.

I've been out of town for the last six days, so I checked SG the night before I left - six days post-pitch (harvested Bell's yeast) - and was down from 1.064 to 1.011. That's a little higher attenuation than expected, so perhaps having my mash temp come in a little low had something to do with that. I did pitch a really healthy starter at high kräusen, so that may have had a big role to play, as well.

I'm really curious to see what the end product is like. The issue I had with my last beer having a very high FG is still in question, and this batch was fermented with the same yeast using the same starter process with approximately the same pitch rates. I have a hard time believing that it was all to do with yeast health, but maybe I'll end up chalking up that high FG on the brown ale to an anomaly...
 
After reading this thread, I decided to go ahead and dough in all at once on my last batch - a Centennial IPA with a 12.5 lb grain bill and a 1.75 gallon sparge brewed 12 days ago. I heated my strike water to about 3 degrees shy of what Priceless Brewing indicated just to see if I'd hit my mash temps with the quick dough in.

Negative, Ghostrider.

I came in a couple degrees short on mash temp. I attribute this to having to stir pretty vigorously for a few minutes to get rid of doughballs. So I hit the burner and brought temp up to my planned temp of 150F within less than a minute.

I've been out of town for the last six days, so I checked SG the night before I left - six days post-pitch (harvested Bell's yeast) - and was down from 1.064 to 1.011. That's a little higher attenuation than expected, so perhaps having my mash temp come in a little low had something to do with that. I did pitch a really healthy starter at high kräusen, so that may have had a big role to play, as well.

I'm really curious to see what the end product is like. The issue I had with my last beer having a very high FG is still in question, and this batch was fermented with the same yeast using the same starter process with approximately the same pitch rates. I have a hard time believing that it was all to do with yeast health, but maybe I'll end up chalking up that high FG on the brown ale to an anomaly...

Sounds like a winner. Thanks for checking in on this thread with your follow-up brew.

I'm not suggesting one should lower the planned strike temperature with a fast dough-in however. Sorry if I was not clear in my OP. I'm thinking that doughing-in fast will bring the temperature down faster to the planned mash-temp. Less exposure at undesirably high temps.

But that's the great thing with a mash-tun that you can direct fire. Really easy to bring temps up. Just stir well during this to eliminate overshoot/uneven heating and kill the heat a degree or so shy of the planned target. It will coast the rest of the way there as the thermal energy in the base of the pot is conducted into the mash.
 
Gotcha, Gavin. I was thinking that quick dough-in might mean you should strike a few degrees shy of where you might otherwise be. Glad to have it ten that misconception cleared up!

Priceless...yet another example to show that your info is quality.
 
On my most recent mash I heated my water to 158 and it took me about 4 minutes to add in 12 pounds of grains. To me this was a normal speed and I dropped 4 degrees when measured 10 minutes later.
 
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