Belgian Yeast (maybe others) Lower Attenuation Since Changing Brew System

[Bobo1898]

I've been brewing since 2009 with my process slowly evolving to improve my beer over the years. Three or four years ago, I switched up my mashing setup. I went from stainless pot covered in blankets (since 2009) to a RIMS system. In my previous setup, I would do step mashes by adding boiling water, to hit my marks. With the RIMS, the boiling water is obviously no longer necessary. I love my RIMS system but some for some reason I'm not getting the attenuation I used to get.

Over the years, I've had a rolodex of Belgian brews that I would make---Saison (Wyeast 3724/WLP 565), Patersbier, Dubbel and Quad (Wyeast 3787/WLP 530)--in between various other brews. In the case of these Belgian ales, I would make starters for each Wyeast and WLP and pitch both. I do a step mash for all of these beers and all of them are open fermented:

SAISON STEPS (Wyeast 3724/WLP 565)
122 - 15m
131 - 15m
144 - 20m
148 - 30m
152 - 20m
163 - 30m

9% of the fermentables is candi syrup. Start ferment at 62 before slowly raising temp to 95 degrees over 7-9 days. The beer is open fermented for 3-4 of these days, cropping every 24 hours, before capping. Yeast is harvested for bottling. On the previous system, my attenuation was 94%. On the RIMS system, my attenuation is now 81%. I understand that 81% is still 81%, but I'm not sure I understand the sudden dropoff.

PATERSBIER/DUBBEL/QUAD STEPS (Wyeast 3787/WLP 530) - generally the same steps for all
122 - 15m
131 - 20m
148 - 75m
152 - 20m
163 - 30m

Candi syrup makes up 10% (patersbier), 7% (dubbel) and 16% (quad) of fermentables. Start ferment at 68 before slowly raising temp to 84 degrees over 7 days. Open ferment for 3 of these days, cropping every 24 hours, before capping. Yeast is harvested for bottling and for the next brew---I brew the patersbier to use the yeast for the dubbel or the quad. On the previous system, my attenuation was 88% (patersbier), 85% (dubbel) and 85% (quad). On the RIMS system, my attenuation is 74% (patersbier) and 78% (dubbel). I have not brewed the quad on the RIMS system yet since it's quite an investment of time.

I also make a Kolschbier and when I switched to this RIMS system, again, I'm running into lower attenuation.

KOLSCH STEPS (Wyeast 2565)
145 - 60m
158 - 30m

Closed ferment at 60. When fermentation is close to complete, slowly raise temp to 68. On the previous system, attenuation was 85%. On the RIMS system, attenuation is 75%.

I have not made any major changes to my process since switching to the RIMS. Fermentation practices are the same and my mash pH is fine. Am I destroying the enzymes? My element isn't scorched or anything. I have a good flowrate and my temps are stable. My brewhouse efficiency went up a few points but I've readjusted my equipment profile in Beersmith to offset after the first couple brews. I'm hitting my numbers going into the fermenter but the yeast is not finishing the same way.

Additional note---I rouse the yeast after each crop when when open fermenting.

 

[mashpaddled]

I'm not an expert in RIMS setups and I'm sure we can get some brewers who are to chime in here.

Are you only having this issue with these styles, or is your attenuation generally worse on all beers? For these beers I wonder if running the RIMS but also adding boiling water in steps would produce the same or better attenuation. I know Dupont runs a slow continual temperature increase, which is more like your RIMS than an infusion step mash, but they have no problems with attenuation.

 

[Bobo1898]

Are you only having this issue with these styles, or is your attenuation generally worse on all beers?

Good question @mashpaddled ! I went back and took a look at a few. It seems like it's mostly with the styles I mentioned in my original post but some other styles are low with caveats:

DOPPELBOCK (WLP 833) - 69% attenuation (never brewed this on the previous system)
122 - 15m
131 - 20m
145 - 60m (decoction step held at 145 for 15m before boiling for 30m)
156 - 45m (decoction step held at 150 for 15m before boiling for 30m)

Ferment at 48 for close to two weeks. Slowly raise temp and finish out at 68. Attenuation for this yeast ranges 70-76% so I'm teetering on the low end. I'm not complaining too much about this, as it took 3rd place in its category.

IMPERIAL STOUT (Safale 05) - 73% attenuation (previous system 70% but ABV on this is 12%)
150 - 120m

Ferment at 64 for 5 days then slowly raise to 68/69 to finish out.

My IPAs have expected attenuation, and in some cases increased, but it's tough to use this data because I've switched yeast for them and the grain bill is always changing. The last one I brewed was a DIPA---84% attenuation with WLP 001 (what I will exclusively use for the style) with the following mash steps:

146 - 90m
156 - 20m

The last DIPA I brewed on the previous system, with a somewhat similar grain bill---80% attenuation with Safale 05 (I no longer use for this style) single infusion at 150 for 60m. Fermentation schedule for both of these are similar to the stout above.

For these beers I wonder if running the RIMS but also adding boiling water in steps would produce the same or better attenuation.

This raises another good point. On the previous system, I'd be disturbing the grain bed when adding boiling water because I'd be stirring and remixing the mash when that would happen. I don't know if that would do anything to reinforce simple sugars given the temps I was mostly stable at. On the previous system, with a single infusion, I'd lose 1 degree maybe 2 over the course of an hour.

The RIMS system is very stable. I'm using a temp probe at the exit point of the RIMS tube AND a probe in the tun. I rely on the probe in the tun. My exit probe is set to 1-2 degrees higher in the winter but in the summer it's spot on with the probe in the tun.

In regards to your Dupont comment, yes---theoretically I shouldn't run into attenuation issues like I've been with my saison because it's simliar to the continual rise that Dupont incorporates (obviously not expecting the same results, but my attenuation shouldn't be that far off from before). Not sure how their system is set up, but it's possible they rake throughout the mash. Which relates back to my "disturbing the grain bed" comment when I would add boiling water on my previous setup. Did remixing the mash help in attenuation?

Again, keep in mind that I'm hitting my target OG.

 

[Bobo1898]

Bump

 

[Bassman2003]

I do not have a RIMS setup but have read others' concerns about denaturing enzymes with the implementation. The nature of running a small amount of wort through higher temperatures does send up a bit of a red flag to me and the most delicate enzymes are the beta enzymes and limit dextrinase that have a large attenuation impact.

Do you have any alternate approaches you can employ to test? Maybe prepare infusion water to get you up to the beta rest and then turn the RIMS on for the remainder of the mash? It might be a long process but the only way to know is to alter your brewing process and judge the resulting beer.

I have gone through quite a few systems over the years. sucks but don't feel bad if you find the need to change again. No point in forging ahead with a system that is letting you down.

 

[Bassman2003]

Or, maybe try a brew starting at 135F or even the beta rest. The lower the rest temp the higher the temperature difference between the wort and the RIMS blast. If you do not hang out in the lower temps, theoretically you would not have the opportunity to damage enzymes. This might be a better and easier way to test on a brew.

How do you get to your initial dough in temps? Do you have an HLT?

 

[DonT]

Do you take gravity readings during the mash?

 

[doug293cz]

My thinking is similar to @Bassman2003 's. You may be denaturing the enzymes while transiting the RIMS tube. Although I think it is less about beta amylase, and more about limit dextrinase, as limit dextrinase is the enzyme which reduces the total amount of dextrin left in the wort, and it is the dextrin that is unfermentable.

Where exactly (including distance), in relation to the tip of the heating element, is the temp probe in the RIMS tube? What temps do you see exiting the RIMS tube when you are stepping up the temperature? Can you post some pics showing the overall and details of your RIMS tube?

Brew on

 

[Bobo1898]

Thanks for the responses, Peoples!

How do you get to your initial dough in temps? Do you have an HLT?

I do not have a HLT. I run the water through the RIMS with the element on til I reach my first step temp. When I reach that temp, I turn the element off, my pump off and close my drain valve. I slowly add my grain. Once I'm confident there are no dough balls, I'll open the drain valve and turn the pump on. I'll adjust my flowrate and get as close to 1.5 quarts/minute. When I reach that flow rate, I'll turn the RIMS element back on.

Do you take gravity readings during the mash?

Not during the mash. But I do take gravity readings pre-boil and post boil. I try to do readings during first runnings and sparge runnings, but I've been doing it less and less since my pre-boil numbers and post boil numbers are spot-on.

Where exactly (including distance), in relation to the tip of the heating element, is the temp probe in the RIMS tube? What temps do you see exiting the RIMS tube when you are stepping up the temperature? Can you post some pics showing the overall and details of your RIMS tube?

The probe is at the exit point of the RIMS. I'm currently traveling so I can't give you the distance from the element, but as you can see in my pictures, it's the RIMS system from Brewhardware (if anyone is familiar, outside of Bobby). I can measure the distance when I'm back later this week. As for the temps, I'm seeing at the exit point, it doesn't go beyond 5-6 degrees above what I set it to, but only early in the process. So for example:

If my step mash is:

122, 131, and 149

When I first heat to 122, it may jump to 128, then drop back down when the element goes off, then jump back down til it kicks back on. Then jump to 126, then down, then 124, then down. Then it fairly goes stable at 122. When I go to 131, the jump above is less---135/136---before stabilizing. When I go to 149, it goes above a few degrees until it stabilizes. Any temp above these, it doesn't any further above. And I do not mash out. Again, in the winter, I will set the temp higher on the RIMS to get the temp I want in the tun. So if I hit 122 in the tun, I may turn the RIMS to 125. In this case, the RIMS out is reading 130/131 when it first reaches, then starts to stabilize.

The only time I've had temps go out of control is when my crush was too fine. I've adjusted my grind to avoid this. In regards to the image of the locline returning wort, that's an example of when the crush teetered on too fine (this was when I first got the RIMS). I don't have the white powdery stuff anymore and my return is no longer around the sides (I was playing with positions and flowrates with that picture). I currently return in the center with the 1.5 quarts/minute.

Do you have any alternate approaches you can employ to test?

@Bassman2003 I have the way I previously mashed to compare, as noted in my original post. Another option would be to use my boil kettle as a HLT to heat up my strike water, then move it into the mash tun.

The lower the rest temp the higher the temperature difference between the wort and the RIMS blast.

I am doing step mashes and don't mash out, so technically, I'm not reaching anything over 163/164 because by then, I'm stabilized. Each step rest takes 15 minutes to rise up at the flowrate I'm using.

 

[Bassman2003]

Let us know how it turns out.

 

[Bobo1898]

@Bassman2003 I hit the wrong button combo and didn't get to write my whole response.

Please see my full response above.

 

[Bassman2003]

Thanks. My educated guess would be that the protein rests are what is hurting you. Try doughing in at 135F or your beta rest and I think your issues might go away. What I am thinking is - the RIMS is heating the wort up in the small area of the element but the grain bed is below gelatinization temps. So nothing is being accomplished. If you dough in at the temps of the first real conversion rests, you will not damage any enzymes as they will be in their normal operating ranges.

With modern malts you do not need the protein rests outside of maybe some special malts bills like a wheat heavy beer.

Can I ask why you are mashing with an emphasis on the lower rests and not using alpha and a mashout? I would suggest a 144F, 149F, 161F, 172F mash schedule for maximum attenuation.

 

[doug293cz]

The probe is at the exit point of the RIMS. I'm currently traveling so I can't give you the distance from the element, but as you can see in my pictures, it's the RIMS system from Brewhardware (if anyone is familiar, outside of Bobby). I can measure the distance when I'm back later this week. As for the temps, I'm seeing at the exit point, it doesn't go beyond 5-6 degrees above what I set it to, but only early in the process. So for example:

If my step mash is:

122, 131, and 149

When I first heat to 122, it may jump to 128, then drop back down when the element goes off, then jump back down til it kicks back on. Then jump to 126, then down, then 124, then down. Then it fairly goes stable at 122. When I go to 131, the jump above is less---135/136---before stabilizing. When I go to 149, it goes above a few degrees until it stabilizes. Any temp above these, it doesn't any further above. And I do not mash out. Again, in the winter, I will set the temp higher on the RIMS to get the temp I want in the tun. So if I hit 122 in the tun, I may turn the RIMS to 125. In this case, the RIMS out is reading 130/131 when it first reaches, then starts to stabilize.

Given this information, I will have to retract my original conjecture. I don't think you are heating the wort enough in the RIMS to damage the enzymes (any more than a typical infusion mash would.) I don't have a new theory to offer at this time.

Brew on

 

[Bobo1898]

Can I ask why you are mashing with an emphasis on the lower rests and not using alpha and a mashout? I would suggest a 144F, 149F, 161F, 172F

Just to be clear, my last post used lower steps as an example (poor choice on my part). I don't think I'm doing an emphasis on lower rests, but I understand your point that they aren't necessary. My original post, has the full range, minus sparging. These are the steps I use:

122, 131, 144, 148, 152, 163 for the Saison
122, 131, 148, 152, 163 for the Belgian ales

As for not mashing out, apologies for not clarifying. I don't mash out in the traditional sense because I batch sparge. My batch sparge is at 168--- I run and recirculate this for 10 minutes so technically I'm mashing out with that. I don't recall this ever going above 168.

Doing the full range of steps was inspired by DuPont's supposed continuous rise in temp during their mash schedule. I had great results doing this with my Saison and I stuck with the process (but I was doing steps as oppose to a continuous rise). Before this, I did my Belgian ales a variety of ways, including single infusion and decoctions in some cases. The decoction and step mash versions had more depth, but I preferred the step mash without decoction. Yes, with modern malts a protein rest is likely unnecessary. Some people say steps don't matter and others swear by them. I've found success with them so I've stuck with them for these styles.

Maybe I lose my 122 step and start at 131 or at 144 to see if there's a difference in attenuation. To compare mash schedules, it seems my IPAs have more expected attenuation and I don't do protein rests with those---but with a different yeast, obviously, and grain bill.

What I am thinking is - the RIMS is heating the wort up in the small area of the element but the grain bed is below gelatinization temps. So nothing is being accomplished.

This is possible. Again, I have another probe in the tun to monitor the actual mash temp. Yeah, maybe I could be at those gelatinization temps for too long. I try to include the 15-20 minutes it takes to raise the temp, at my flow rate, into account for the step time. So if my step is supposed to be at the duration of 30 minutes, I'll start the rise 10-15 minutes into that step because it takes 15-20 to raise. Does that make sense?

Brew on

Indeed. It's the only thing left to do....sort of.

 

[Bassman2003]

Thanks for clarifying. I was confused since your earlier post said you did the entire mash range. No worries on the mashout either. I wish I could offer more help with your issue but my only guess is the actual RIMS approach.

I have been studying European mashes for a long time and I am prone to wanting to do every step ever thought of - (95F dough in...) but I restrain myself to not go below 135F unless I and doing a feurillic acid rest at 111F for a hefeweizen. My brew setup has been electric for a long time and I can share experiences with wort scorching. It appears to me that the only time I am at risk of major scorching is when I am below gel temps. This is also when the wort has not cleared and a bunch of particles are flying around in the wort. The temperature differential between the element (which is constant) is magnified the lower one goes with the wort temp. I only boiling water infuse the 111F rest up to beta and all is well in my system. I might be wrong but maybe this is playing out in some way with the RIMS? I can't think of another reason why your attenuation would be affected.

Maybe stirring but your efficiency would show differences as well.

At least it is easy enough to try a different starting point and if you like it, the brew day will be shorter.

 

[Bobo1898]

I only boiling water infuse the 111F rest up to beta and all is well in my system.

Just want to understand this correctly, are you saying you use boiling water to reach steps under 135 as I've done in my previous system? Then do temp raises with your element after 135? If this is correct, I can try this method. And/or try what I suggested in my previous post---skipping protein rests altogether (when not using wheat).

 

[Bassman2003]

I have an HLT, so I dough in at 111F with about half of the strike water, rest for 20 min. then add the remainder of my strike water (which is boiling) to bring the mash up to the 140's. I am a low oxygen brewer so boiling the strike water is good to remove the O2 anyway. So I do not turn my element on until the beta rest. For every other beer I dough in at the beta rest. I might try some 135F doughins as that is a favorite of the low Ox crowd.

 

[JohnDBrewer]

How long does it take to raise your mash bed between steps? I have a RIMS and never try to raise the temp by more than 1.5*-2*/minute.

What gap do you use for your grain crush? I run my gap at .05-.055 to get good flow through the grain bed. I've messed around with tighter and wider, but this is the sweet spot for my system. I average high 80's % for efficiency on 5g batches and high 70's for 10g or big beers (high gravity). My vessel is a keggle.

What's the significance of 1.5qrt/minute for flow rate?

I'll have to measure my flow, but I run mine wide open. Next time I brew I'll measure, but it seems much faster than this.

I also never stir the mash bed after recirculation starts. I have the ability to bottom fill my mash. Once my strike water is loaded, I stir a couple times, let the mash hydrate for 10-15 minutes, stir again than start the recirculation. Usually ramp it up to wide open over a couple of minutes. If I have a lot of wheat or rye I use rice hulls.

 

[Bobo1898]

How long does it take to raise your mash bed between steps? I have a RIMS and never try to raise the temp by more than 1.5*-2*/minute.

What's the significance of 1.5qrt/minute for flow rate?

At my flow rate, it takes 15-20 minutes to raise the temp (for higher raises). In the summer it sometimes takes 10 minutes. The reason I do 1.5qts/minute is so the grain bed isn't compacted. I ran it wide open during my first two brews on it and noticed that I had severe channeling along the edge by the return point. The grain bed was completely uneven and my numbers were way off. It was recommended to use a flow rate that wouldn't compact the grain, or make it uneven. Once I harnessed the flow rate, my numbers were better. To your point, raising the temp with it wide open only took 1-2 minutes. But I could not find a way to do this without compacting the grain bed and losing a lot of efficiency.

I would prefer to run mine wide open. If you have advice to avoid channeling/compacting the grain, with it wide open and still maintain decent efficiency, please share!

I know that Kal from Electric Brewery runs his wide open, as do others (like yourself) without issue. What's the length of your return hose? He obviously has a different system, but with his return hose being so long and wrapped around the interior circumference of the mash, perhaps the flow rate naturally slows which allows for him to not get any grain compacting or channeling? But in his videos, it still looks pretty fast that I would think he runs into this issue. His mash efficiency is somewhere in the high 90s I think, but I can't remember.

What gap do you use for your grain crush?

0.035 or 0.040---I used to do a finer crush on the older system which was too much for my current RIMS. Fortunately, I was running it wide open on the finer crush, but if I had used my current flow rate, I bet I would have had stuck mashes and a scorched element. I've been running 0.035-0.040 for a bit. I've thought about going closer to 0.050 but just haven't made the jump yet, mostly because I forget to do it until it's too late.

I also never stir the mash bed after recirculation starts. I have the ability to bottom fill my mash. Once my strike water is loaded, I stir a couple times, let the mash hydrate for 10-15 minutes, stir again than start the recirculation. Usually ramp it up to wide open over a couple of minutes. If I have a lot of wheat or rye I use rice hulls.

I don't stir after recirculation starts. Unfortunately, I do not underlet my mash, but this is absolutely on my list of things to move towards (want to get another pump first). My boil kettle is still propane and happens outside while my mash is electric and is done inside. Switching to an electric boil is an on-going internal debate of whether I should make the jump. Supposedly you don't get the same caramelization with electric that you can with propane, but I don't know if it's that prominent on the homebrew level. Plus, if I go electric, I don't have to carry my full boil kettle outside.

I do use rice hulls for all brews, out of habit, from the previous system. As I said in an earlier post, I'm heating my strike with the RIMS and slowly adding the grain. I'm probably lightly stirring for 5-10 minutes or until I don't notice any dough balls.

I average high 80's % for efficiency on 5g batches and high 70's for 10g or big beers (high gravity).

Is this mash efficiency or brewhouse efficiency?

 

[JohnDBrewer]

That's my mash efficiency. I'll measure my flow rate next brew day.

I also fly sparge so for my mash I shoot for a little over 2-inches of water above the grain bed (1.25-1.3 quarts/pound.)

A bigger crush may help with grain compaction, but so should the rice hulls.

My return line is a hose which just lays on top of my grain bed, below the waterline and flows clock-wise.

The 10-minutes between steps of 10* sounds a bit hot. Seems like a faster flow rate would increase this time to raise the temp and wort would be exposed less time to the heating element? I also use propane to assist when i do me steps.

 

[hottpeper13]

I too do boiling water additions for step mashing and was going to upgrade to a rims system until I brewed with a friend that had one. He said his ADF had gone down and didn't know why. At clean up he took it apart and the bend of the element was crusty. He was trying to get the step in 10 min or less like the big boys. I think most of my buddys that recirc have gone to the continuous rise from a dough in around 131-135 up to mashout with good attenuation.

 

[VTMongoose]

The first thing I would want to check is what actual temperatures the grain are at throughout the mashing process. I bought a long electronic candy thermometer off Amazon specifically to measure the temperature of my mash. I don't care what the controller says, you can easily have cold spots if you don't have perfectly even flow (due to dough balls, not enough rice hulls, etc). I've seen it where 75% of my mash read within a degree of the 150°F I was commanding on the controller, but there was a dead spot somewhere (near the bottom) that was only 122°F. Obviously when something like this happens, it's my cue to give the mash a good stir. But you can resolve the problem at one step, and depending on the grist, have it come back at your next step. Some of my wheat beers use 5 steps and historically some batches have been a nightmare just to get them up to temperature.

Also, get a cheap refractometer and use it to track your SG throughout your mashes. If you're at your beta-amylase rest for 40 minutes and you're only seeing 1.020 in a beer you're expecting to hit a pre-boil grav of 1.047, something is wrong, and it's your cue to investigate what that might be.

 

[Bobo1898]

The first thing I would want to check is what actual temperatures the grain are at throughout the mashing process.

Yeah, I have a separate thermometer in the tun, but you bring up a good point a little later---perhaps somewhere buried deep is a cold spot. I do check a few spots, but I'm not disturbing the grain at each step. The first step is probably the most thorough I'm checking in the tun. I will say, I place my tun on top of two layers of reflectix. It's not wrapped in it, but just resting on top of it. That being said, it still is likely not even throughout at other steps (mash agitator anyone?).

Also, get a cheap refractometer and use it to track your SG throughout your mashes.

I will start tracking throughout but I am hitting my numbers pre-boil, though.

My return line is a hose which just lays on top of my grain bed, below the waterline and flows clock-wise.

@JohnDBrewer is your hose line long?

 

[JohnDBrewer]

My entire line from leaving the mash tun to the RIMS tube is about 5 feet, then returns probably 4 feet, all hard piped, without the hose laying on the grain bed. Temp is taken at exit of MT.

 

[Bobo1898]

Thanks for all the responses. I'm starting to fall in line with the idea that my tun, somewhere, is at gelatinization temps or lower. I'm getting good attenuation on the IPAs I've made on this---which if using steps doesn't go below 145. On my previous system, I was always stirring the mash with each step. Now I'm not doing that and likely to have cold spots somewhere. And my flow rate may further hurt this.

I don't know if running wide open would resolve this or not. If it did, a problem remains in that I don't know how to run wide open without grain compacting, channeling and creating large sand dunes.

Next Belgian brew day, I'll try adding boiling water and stirring for the lower temps until I reach my beta steps. Once I get to 140-something, I'll use the RIMS element. Might be a while, but I'll try to update in a few months.

 

[Bassman2003]

Yes keep us posted. Hope it works out.

 

[Bobo1898]

UPDATE. Sort of.

I'm leaning towards gelatinization as being the culprit. Made a saison recently and had improved results.

Heated my strike water to 113° and rested WITHOUT recirculation or heat. I accidentally added all my strike water for this step (I meant to use boiled water additions til I got to 131) so when it came time to get to 131, I had to recirculate and add heat.

OG @ 1050
FG @ 1.006 which is 87.6% attenuation

I wrote to my future self within the recipe to mind my strike water volume so I can utilize water additions to get to next steps. While 87.6% isn't my previous 94% attenuation, it's definitely an improvement over my recent 81% which I felt was low for this yeast/style.

Thank you for helping me troubleshoot this.

The Belgian yeasts were my concern because of the range of steps I use. But a few other brew styles had the following results:

KOLSCH (estimated attenuation is 83.8%)
OG @ 1046
FG @ 1011 which is 75.4% attenuation

Lowest I mash this is at 145°.

ESB (estimated attenuation is 76.9%)
OG @ 1047
FG @ 1.011 which is 75.9% attenuation

Mash is single infusion at 152°.

 

[Bassman2003]

Looks like a win. 1.006 is great.