Tips for cleaning a plate chiller

[douglasbarbin]

How come a company like Duda diesel hasn't come out with a heat exchanger that can be taken apart? I know they make the larger ones that separate, but why not the smaller model ones. Seems like it would be a desirable product.

I think the expense is prohibitive. I've read that Shirron did some prototypes a while back, but the expected retail price was going to be in excess of $400, so they scrapped it. As you can imagine, there isn't much of a market for a $400 chiller to cool 5 or 10 gallons of wort when the only advantage is that it cools a couple of minutes faster than a $100 chiller.

 

[ajdelange]

Because of the polarity of the mixture, water and alcohol like to stick together. When this mixture is allowed to evaporate, it will do so as a single new component, without either one being preferentially left behind.

Not so (except at the azeotropic point). Raoults law says that the vapor over a binary mixture will be richer in the component with the higher saturated vapor pressure, in this case, alcohol. Thus if we have mixture of 10% ethanol and 90% water the vapor will have a composition of, say, 20% ethanol and 80% water (those aren't the actual numbers but you can look them up). As the vapor rises in the column it reaches a point where the temperature is equal to the dew point of the enrichened vapor and condensation takes place. This now enrichened liquid refluxes until it reaches its boiling point which is, as the mixture is richer than the water in the distilling flask, lower than the boiling point in the flask. The vapor from this boiling is richer than the condensate and so as it rises it condenses at an even lower temperature and so on until the azeotropic concentration is reached. At that point the vapor is not richer in alcohol than water and no further enrichment is possible. Note that it is deviation from Raoult's law (which only applies to ideal mixtures - ones in which the molecules of the two components interact in exactly the same way as the molecules of the individual components) that cause the azeotropic behavior.

 

[johnodonovan]

I thought most people run their boiling wort through them for 15m before chilling. That does the sanitization for me.

This is what I do and I've never had an issue with off flavors. I have the larger duda chiller (which is awesome btw) . In my opinion the high temps just before chill time are the best option. I also flush with PBW for a few mins after use, but I think this is less critical.

 

[TexasWine]

Not so (except at the azeotropic point). Raoults law says that the vapor over a binary mixture will be richer in the component with the higher saturated vapor pressure, in this case, alcohol. Thus if we have mixture of 10% ethanol and 90% water the vapor will have a composition of, say, 20% ethanol and 80% water (those aren't the actual numbers but you can look them up). As the vapor rises in the column it reaches a point where the temperature is equal to the dew point of the enrichened vapor and condensation takes place. This now enrichened liquid refluxes until it reaches its boiling point which is, as the mixture is richer than the water in the distilling flask, lower than the boiling point in the flask. The vapor from this boiling is richer than the condensate and so as it rises it condenses at an even lower temperature and so on until the azeotropic concentration is reached. At that point the vapor is not richer in alcohol than water and no further enrichment is possible. Note that it is deviation from Raoult's law (which only applies to ideal mixtures - ones in which the molecules of the two components interact in exactly the same way as the molecules of the individual components) that cause the azeotropic behavior.

You, sir, are 100% correct. My apologies if I confused anyone. It seems that my brain was stuck in continuous distillation versus batch distillation. In continuous distillation the vapor and liquid on any given theoretical stage are in equilibrium and have the same composition. I mistskenly applied that to a simple evaporation issue.

I still think rubbing alcohol could be the solution to water hanging around in plate chillers!

 

[kombat]

I still think rubbing alcohol could be the solution to water hanging around in plate chillers!

I suppose, if you didn't mind the medicinal alcohol flavour carrying over into your beers. I honestly can't believe we're even talking about this - it seems like such a terrible idea on the face of it. Isn't rubbing alcohol extremely toxic to humans?

I've always cleaned my plate chiller by backflushing with hot water for a couple of minutes, then hot Oxyclean for 20 minutes or so while I clean the boil kettle, then rinsing with cold water. I dump out as much water as I can, but I store it wet, with the caps uncovered. Like passedpawn, I sanitize by circulating boiling wort through it for 5-10 minutes toward the end of my boil.

That said, last brew day I actually looked inside the ports of my plate chiller. The "water" ports, of course, were still bright silver, like the first day I used it. The "wort" ports, however, had a tan hue to the metal. Knowing that PBW is more potent than Oxyclean, I actually mixed up a couple of gallons of hot PBW solution and recirculated that through the chiller for 20 minutes. I then switched to a rinse with hot water, and discovered all kinds of extremely thin, brown flakes floating in the rinse water.

It appears that a very thin film of wort had built up on the walls inside the plate chiller, and Oxyclean wasn't getting it out. But a PBW wash did the trick. However, it took several rounds of dumping and refreshing the rinse water before no more flakes were coming out of the chiller.

I guess what I'm saying is, for those of you flushing/washing with Oxyclean, try a round with PBW every once in a while to REALLY get it clean.

 

[TexasWine]

I suppose, if you didn't mind the medicinal alcohol flavour carrying over into your beers. I honestly can't believe we're even talking about this - it seems like such a terrible idea on the face of it. Isn't rubbing alcohol extremely toxic to humans?

There would be no flavor nor would it be toxic because it would all evaporate, leaving nothing behind to impart a flavor or kill you.

This is gonna sound silly, but try wiping a plate with a swab of rubbing alcochol, let it evaporate, and lick the plate. You'll taste nothing except the plate (and any food your dishwasher didn't handle).

I've got a plate chiller coming tomorrow. I'll dump some water in it, empty it, and chase the water with some rubbing alcohol and report back with the results.

And, as with most things, I'm sure there is a threshold at which consumption of isopropyl alcohol becomes dangerous. From what I've read it looks like drinking 8 ounces (not sure what concentration) can kill.

 

[passedpawn]

I've got a plate chiller coming tomorrow. I'll dump some water in it, empty it, and chase the water with some rubbing alcohol and report back with the results.

How will you assess "results"?

 

[Saboral]

This is what I do and I've never had an issue with off flavors. I have the larger duda chiller (which is awesome btw) . In my opinion the high temps just before chill time are the best option. I also flush with PBW for a few mins after use, but I think this is less critical.

Agreed, I just run boiling wort through it for a few minutes before going to chilling. I also started using a hop spider which has helped a lot. I put quick connect fittings on the hose side and camlocks on the wort side. I built a cam to quick connect adapter that allows me to immediately back flush and flush the plate chiller the moment chilling is complete. I don't get any gunk. My only issue thus far is the first time I used it I failed to drain the water after cleaning. Well a garage in December-January is a bad place for a plate chiller containing water. Now I give the chiller a blast of high pressure air from my compressor following cleaning to get all the water out.

 

[kombat]

I put quick connect fittings on the hose side and camlocks on the wort side.

Just out of curiosity, why did you decide to use different fittings? Why not just use one or the other for your whole system? I use quick disconnect fittings across the board to make it easy to swap hoses around. Why did you go with half-and-half?

 

[PlexVector]

There would be no flavor nor would it be toxic because it would all evaporate, leaving nothing behind to impart a flavor or kill you.

This is gonna sound silly, but try wiping a plate with a swab of rubbing alcochol, let it evaporate, and lick the plate. You'll taste nothing except the plate (and any food your dishwasher didn't handle).

I've got a plate chiller coming tomorrow. I'll dump some water in it, empty it, and chase the water with some rubbing alcohol and report back with the results.

And, as with most things, I'm sure there is a threshold at which consumption of isopropyl alcohol becomes dangerous. From what I've read it looks like drinking 8 ounces (not sure what concentration) can kill.

Everclear from the liquor store would be the safest thing to use. I don't know the cost these days, but used to use it in HS & college to make PJ and clean tape heads.

 

[Saboral]

Just out of curiosity, why did you decide to use different fittings? Why not just use one or the other for your whole system? I use quick disconnect fittings across the board to make it easy to swap hoses around. Why did you go with half-and-half?

Well,

1. I already had a significant investment in camlocks on my system.

2. I like having incompatible fittings on the wort versus water side. A bit of insurance against a catastrophic mistake in the heat, pun intended, of the moment.

3. The quick connect male fitting makes a bit of higher pressure nozzle on the end of my hose for cleaning purposes.

4. Quick connects come stock in 3/4" hose threads versus camlocks which are commonly available in pipe thread.

Hope that provides a bit of insight to my madness.

 

[Gavin C]

Wouldn't having the same type of connects on the water and wort sides allow deliberate switching the side each brew. One brews wort in is the next brews water out port. A back-flush each time.

I am looking to change my hose barbs to cam-locks for this reason at some stage. I have switched the ports over on the one ocasion I have baked it in the oven. I was taking the connects off anyway to prevent the Teflon tape from melting(not sure if it would have)

I am not too worried by water remaining in the chiller. An impossible task to remove it all I think and one that is impossible to verify as complete.

I too use a hop spider to keep most of the crud out, circulate boiling wort for 5 minutes or so at the end of the boil, backflushing with oxyclean after a good rinse after each brew as I am cleaning up. I just let the pot, tubing and chiller sit overnight with oxyclean in the setup.

Edit: I should note that I don't use a garden hose for the cooling water. I use vinyl tubing attached to the kitchen faucet. (narrower than a garden hose). A garden hose would need wider fittings than the 1/2" I have

 

[TexasWine]

How will you assess "results"?

I'll shake it (like a Polaroid picture), both before and after adding the rubbing alcohol. If I hear something sloshing around both times then I'll know it didn't work.

Also, I'll throw it on my scale before and after. I know there's a limit to the scale's resolution, so I'm not sure that'll tell me anything.

 

[Duda_Energy]

How come a company like Duda diesel hasn't come out with a heat exchanger that can be taken apart? I know they make the larger ones that separate, but why not the smaller model ones. Seems like it would be a desirable product.

I think the expense is prohibitive. I've read that Shirron did some prototypes a while back, but the expected retail price was going to be in excess of $400, so they scrapped it. As you can imagine, there isn't much of a market for a $400 chiller to cool 5 or 10 gallons of wort when the only advantage is that it cools a couple of minutes faster than a $100 chiller.

Duda Diesel employee here, and I can confirm this is exactly the case. We looked into units that could be disassembled, but that pretty much eliminates brazing. So now you have a unit that isn't brazed together, that is still supposed to transfer heat efficiently and withstand significant pressures for the guys who do freon chilling.

If someone ever comes up with a design for a unit that can be disassembled, can hold pressure, still works efficiently, *and* costs less than $500 to make for what should retail around $100, shoot me an email. We'd love to make them.

 

[Gavin C]

Duda Diesel employee here, and I can confirm this is exactly the case. We looked into units that could be disassembled, but that pretty much eliminates brazing. So now you have a unit that isn't brazed together, that is still supposed to transfer heat efficiently and withstand significant pressures for the guys who do freon chilling.

If someone ever comes up with a design for a unit that can be disassembled, can hold pressure, still works efficiently, *and* costs less than $500 to make for what should retail around $100, shoot me an email. We'd love to make them.

Great info. Thanks for that Duda_Energy. Love my Dudadiesel chiller BTW

 

[tally350z]

Duda Diesel employee here, and I can confirm this is exactly the case. We looked into units that could be disassembled, but that pretty much eliminates brazing. So now you have a unit that isn't brazed together, that is still supposed to transfer heat efficiently and withstand significant pressures for the guys who do freon chilling.

If someone ever comes up with a design for a unit that can be disassembled, can hold pressure, still works efficiently, *and* costs less than $500 to make for what should retail around $100, shoot me an email. We'd love to make them.

Cool, thanks for the info.

 

[blkandrust]

Agreed, I just run boiling wort through it for a few minutes before going to chilling. I also started using a hop spider which has helped a lot. I put quick connect fittings on the hose side and camlocks on the wort side. I built a cam to quick connect adapter that allows me to immediately back flush and flush the plate chiller the moment chilling is complete. I don't get any gunk. My only issue thus far is the first time I used it I failed to drain the water after cleaning. Well a garage in December-January is a bad place for a plate chiller containing water. Now I give the chiller a blast of high pressure air from my compressor following cleaning to get all the water out.

Would it be possible to gravity feed boiling wort through the chiller prior to chilling,or is a pump required?

 

[ajdelange]

...and withstand significant pressures for the guys who do freon chilling.

Now that's intriguing. I've thought of doing something like this for years. Will the units withstand normal R410A pressures?

 

[Duda_Energy]

Yes, the 12a and 23a series (the 8" and 12" models) can withstand up to 145 psi, while our larger units are designed to handle 435 psi.

 

[ajdelange]

Thanks. Couple of those, a 2 ton compressor, a txv and some safety switches (and a filter/dryer and some tubing and....) and I could be in business. I will definitely be thinking about this when I get back to VA this fall.

 

[Natdavis777]

I have a 20 plate Duda chiller with no issues. Always cleansed post transfer with PBW and have had no issues. Before it was attached to my stand, it sat in a bucket of sanitizer. I have baked it once (before it was mounted to my stand). That cleared out a lot of hop debris.

FWIW, I keep my chiller mounted to the stand, clear it with PBW at the end of the brew. Before I chill, I recirculate boiling wort for 5 min to sanitize. In 10+ brews with this setup, I have had zero failures.

If for cleaning purposes only, a good bake with a high pressure rinse should suffice.

 

[itsnotrequired]

I'll shake it (like a Polaroid picture), both before and after adding the rubbing alcohol. If I hear something sloshing around both times then I'll know it didn't work.

Also, I'll throw it on my scale before and after. I know there's a limit to the scale's resolution, so I'm not sure that'll tell me anything.

apologies for reviving such an old thread but did you ever try the experiment with the rubbing alcohol? how did it work?