Boil kettle condenser - no overhead ventilation needed

[mabrungard]

I remember a few months ago that you were experimenting with just a cracked lid during a boil, about an inch or so. What's your procedure now?

It is my SOP now. It does work and I haven't found a negative from the method. Based on the research I've done on DMS, the more open boiling phase at the end of the boil is a good method for expelling the final DMS in the wort.

 

[BrunDog]

I used JB Weld to attach the electrical box to the bottom of my e-HLT. It's a weird conical bottomed vessel that I repurposed from work. The conical section is about 1/8" thick and curved, which made a weldless fitting impossible to work - I couldn't get the locknut around the heating element threads with anything more than the gasket on the element. My solution was a gang box extension with JB weld attaching it directly to the vessel. It's been over 10 years and no issues but the HLT never goes above 170F, so I can't say for sure if 212F will cause any issues but I doubt it since JB Weld is rated for much higher temperature.

I've been thinking about your setup; it seems like one important aspect is the have the kettle top sealed fairly well to ensure the steam goes into your condenser. You also want it to be easy to open for hop additions. I'm struggling with this - can't seem to come up with a good solution. What are you thinking for sealing the kettle top in the long run? The plastic wrap doesn't seem like a permanent solution.

I will be using the kettle lid - the plastic wrap was just for testing so I could "see" what was happening and seal it off. Of course I couldn't see anything anyway.

I don't think the lid will be a problem alone. If the condenser creates the appropriate vacuum, there will be little incentive for the steam to escape. I will know more once I bond the flange and run another test with the lid on. Even if a little steam escapes, I don't think that will be an issue. The key is to knock out most of the steam/heat.

 

[Wizard_of_Frobozz]

I'll be interested in hearing the results. I had visions of a complicated lid with hop access door like the pro's use!

Also, here's a picture of my HLT electrical box with JB Weld. Not pretty but it works.

 

[Magua]

Brilliant.

 

[BrunDog]

Ok the bonding seems to have worked well. I did another experiment and learned some things. Moral of the story... math works!

When I fan flat out with 100% duty on the element, the steam overwhelmed the system (currently has the ~6gph sprayer). The temp of the water exiting was at 211, and there was steam escaping through the lid.

Once I lowered the boil to a more normal rate, the system caught up and the flush water temp came down to a more normal ~150 degrees, and there was no steam escaping the lid.

I need to do a legitimate brew before I claim success, but it’s looking like it will be. Interestingly, for those super water conscious, you could automate the water flow rate with a proportional valve (very small Cv range), using the flush exit temperature for guidance. I am probably going to upgrade to the 9 gph and call it a day, but it’s an option. Also interestingly, one minor downside of this system is that it does work passively. Some of the steam prior to full boil leaks out the drain with the sprayer off, so it slows the boil achievement down slightly. A trap in the drain line would reduce this effect.

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[Wizard_of_Frobozz]

Hurry up on that "legitimate" brew! I'm about 50% complete on framing in my new brew room - sure would be nice to know I don't need to bother framing in an exhaust hood!



Great work Brundog!

 

[BrunDog]

Whoa! Give us more details on that sweet space!

 

[augiedoggy]

Just a heads up with the jbweld. Ive seen it used on engine blocks with success so I believe the temps are good to at least 200 but jb weld claims its good for constant temps of up to 500F!
It is food safe and I use it to seal the ends of my stainless thermowells in my conicals.

 

[BrunDog]

Thanks. I used the SteelStik which is temp rated for 300. It has the NSF seal so should be food safe, though it’s technically not in the beer path.

One thing for certain is that stuff set up quick!

 

[Wizard_of_Frobozz]

Whoa! Give us more details on that sweet space!

It's in the back corner of my pole barn. The large bay holds my camper; the brew room will sit behind my truck. I had a plumber run drains for the sinks, toilet, floor drain, and RV, plus the water supply before the floor was poured. Once framing is done, i'll be running 50 amp over to the room and the RV outlet. I'm just now starting to make some real progress on the room - it's been way too hot and humid to get much done over the summer! My hope is to be complete around January, but knowing how much real life seems to interfere, it will likely be a bit later than that...once I'm done, then I will post a build thread for it. :rockin:

 

[BrunDog]

Nice! Looking forward to seeing it come together!

 

[BrunDog]

Well, initial live brew results coming back....

First note: Much drier brew space (my garage). Normally it would be a sauna. So from that perspective, it achieved its goal.

Second note: I needed to turn the boil power down. I mean way down. I mean half!! That’s a nice power savings, though it wouldn’t really translate to much $.

Third note: Boil off rate is greatly reduced. As in half also. I expected to boil off a gallon and ended up boiling off... well, you know the math.

Fourth note: With the above results, we might conclude that the dms and other volatiles were not appropriately carried away. Only time will tell with this beer I did. I will say this though... I tasted the ejected water and it tasted and smelled sweet and corn-like. I think that’s promising but of course not scientific at all. And it had no hop influence because I did a pantry-sweep beer and all I had were summit hops - since they are high Alpha, I only used 0.2 oz. at 20 mins and the remainder at 5.

One thing I will note is some steam does escape out of the flush tube, when that is blocked off some steam begins to escape from under the lid. More to come on that as I add a longer drain but I don’t think it means a whole lot at this point.

Final result once this beer ferments! See my personal build thread for the other experiment I ran with this beer and the whacky ingredient list (that experiment failed, btw).

 

[Wizard_of_Frobozz]

Early results sound promising!

What size heating element do you have in the boil kettle? Sounds like you could downsize that with this setup.

 

[mabrungard]

Second note: I needed to turn the boil power down. I mean way down. I mean half!! That’s a nice power savings, though it wouldn’t really translate to much $.

Third note: Boil off rate is greatly reduced. As in half also. I expected to boil off a gallon and ended up boiling off... well, you know the math.

Fourth note: With the above results, we might conclude that the dms and other volatiles were not appropriately carried away.

Your reduction in power setting mirrors my own. The reduction in evaporation needs to be accounted and planned for. It will take time to figure out what the new starting wort volume needs to be.

Assuming that you boiled an hour, its likely that all the DMS was volatilized, but I'm not sure if it made it out of the 'sealed' kettle. That's why I'm opening my kettle for the final minutes to assure that DMS is expelled.

 

[kevinthestout]

Assuming that you boiled an hour, its likely that all the DMS was volatilized, but I'm not sure if it made it out of the 'sealed' kettle. That's why I'm opening my kettle for the final minutes to assure that DMS is expelled.

But the condenser causes a pressure drop, so the DMS should be more easily evaporated. Some breweries that have installed condensers have been able to shorten their boil. It's mentioned in the LBNL "Energy Efficiency Improvement and Cost Saving Opportunities for Breweries" report.

 

[BrunDog]

Good to know!

 

[mabrungard]

But the condenser causes a pressure drop, so the DMS should be more easily evaporated. Some breweries that have installed condensers have been able to shorten their boil. It's mentioned in the LBNL "Energy Efficiency Improvement and Cost Saving Opportunities for Breweries" report.

This result is odd since DMS boils at 99F. A reduction in pressure within a kettle would only serve to evaporate water more effectively, not DMS. In addition, unless the kettle is sealed, its not going to be under a vacuum.

This information doesn't seem to be accurate, at first glance.

 

[BrunDog]

The quoted document can be found here: https://www.energystar.gov/sites/default/files/buildings/tools/LBNL-50934.pdf

Page 23 discusses DMS, though this is a very different application (steam injection & ejection), so I am not sure this is an apples:apples evaluation.

There may be a minor pressure drop, but as Martin notes DMS is boiled off at a low temperature, so as long as it is captured in the steam, which gets flushed out the condenser drain, we should be good. Of course it will take more time. I will do a lager to see if DMS presents any problem. I know that wont be scientific, but its what I can do, unless someone knows offhand a lab which can test wort samples, in which case I would boil some via open lid and some via the spray condenser.

 

[doug293cz]

This result is odd since DMS boils at 99F. A reduction in pressure within a kettle would only serve to evaporate water more effectively, not DMS. In addition, unless the kettle is sealed, its not going to be under a vacuum.

...

What's special about DMS that it wouldn't boil at lower temps at reduced pressure?

Brew on

 

[shoo]

What's special about DMS that it wouldn't boil at lower temps at reduced pressure?

Brew on

I think this just implies that since the boiling temperature of DMS is so much lower than wort, the additional bonus due to pressure isn’t going to make a difference.

 

[mabrungard]

I think this just implies that since the boiling temperature of DMS is so much lower than wort, the additional bonus due to pressure isn’t going to make a difference.

That is correct. In addition, I've been researching DMS for an article I'm authoring and there is a journal article by Wilson and Booer in which they looked at boil vigor (as evidenced by evaporation rate) and they found that the DMS reduction didn't change in proportion to the evaporation increase. That's why I imply that the change in DMS content due to pressure reduction won't be that significant.

 

[BrunDog]

Thanks Martin. Are their other volatiles which need a vigorous boil or are we concluding that a good simmer is enough?

 

[kevinthestout]

This result is odd since DMS boils at 99F. A reduction in pressure within a kettle would only serve to evaporate water more effectively, not DMS. In addition, unless the kettle is sealed, its not going to be under a vacuum.

This information doesn't seem to be accurate, at first glance.

I seems I misread this section of the report - "savings resulted from shortening the wort heating time". I took that to mean there was a shorter boil, but it's referring to the fact that the wort is pre-heated by the hot condensate from the kettle.

The more significant effect of lower pressure systems is that the rate of decomposition of SMM will decrease rapidly with a drop in boil temperature - more than halved at 95C and reduced 96% at 80C (0.85bar).

To overcome this the Interbrew dynamic low pressure systems alternates between low and high pressure. At high pressure SMM is quickly decomposed and good hot break occurs. The pressure is dropped instantaneously. Small steam bubbles form throughout the boil volume giving a very large steam/liquid interface. This flushes the DMS.

 

[doug293cz]

...

The more significant effect of lower pressure systems is that the rate of decomposition of SMM will decrease rapidly with a drop in boil temperature - more than halved at 95C and reduced 96% at 80C (0.85bar).

...

Interesting. I was thinking, after reading about the low BP of DMS, that it should be removed from the wort very quickly, since wort boils at ~60°C higher than DMS. That would imply that the rate of DMS removal would be controlled by the rate of it's formation from SMM, and your post confirms that in my mind. I expected the decomp rate of SMM to be temp dependent, but the data you reference, says it drops off twice as fast as the "rule of thumb" for organic reactions (rates double or halve for a 10°C temp change.) I found this to be surprising. This might be something for folks who brew at high altitudes to worry about.

Brew on

 

[BrunDog]

Valid points. But do you want to break the news to the brewers in Denver? They think they are the craft capital of the world - this could devastate them! Haha, I am just having fun!! 🤣

 

[doug293cz]

Valid points. But do you want to break the news to the brewers in Denver? They think they are the craft capital of the world - this could devastate them! Haha, I am just having fun!! 🤣

I'm sure the craft brewers can figure out what they need in the way of boil times to avoid DMS, even if they don't understand the science behind it. It's more of a concern on the homebrew level if someone in Denver hears about someone doing short boils, and they try to duplicate it with poor results.

Brew on

 

[sasky7777]

Sub

 

[BeardedBrews]

Interestingly, for those super water conscious, you could automate the water flow rate with a proportional valve (very small Cv range), using the flush exit temperature for guidance. I am probably going to upgrade to the 9 gph and call it a day, but it’s an option.

Could you drop a few frozen water bottles in your drain bucket along with a small pond pump and then drive the spray with recirculated water?

 

[BrunDog]

Yes, but the pump used would need to be able to create the pressure. Also understand the amount of heat getting pulled out. It would take more than a few frozen water bottles.

If water usage were a real concern, I would use a radiator / fan to circulate the water through.

 

[Wizard_of_Frobozz]

Another alternative might be to just capture the water and let it cool off in between brew days; at 9 gph, you will only need to store about 10 gallons. Run it through the condenser, collect the water, let it cool off for a few days, then repeat.

You are wasting the heat that way though. I think the “greenest” solution is to reuse the hot water for cleanup. That way, you are making use of both the water and heat.