HX rubbery smell

[dirtfish]

We think we have traced an off-flavor problem to our heat exchanger. It seems pretty obvious now, but this has been a puzzle for us for a while. We have a strong rubbery smell emanating from the HX every time it is used. The smell increases as temperature of HX increases. The smell comes from the exterior of the HX and also from water that has passed through the HX on either water or wort side. Rubbery taste is also present in water run through either side.

We have cleaned (both water and wort sides) repeatedly with Super CIP, PBW, Acid 5 - and yesterday with Simple Green... I have left the HX packed with PBW overnight, then rinsed with hot water and repacked with Sani-Clean many times. We have no apparent leaks or loss of pressure from packing or otherwise.

We have smell and taste tested a hot water hose that is sometimes used to use to deliver hot rinse water and are sure that the hose is not the source of the odor/taste.

Another thing that happens is, we have had an oily scummy residue form in the discharged water that is saved in the mash tun. This water has made scum rings inside the mash tun that seem to only be able to be removed with acid --- scrubbing with PBW doesn't take them out.

I was trying to avoid taking the HX apart, but maybe this is what we need to do. I don't think I would know if anything looked right/wrong (unless I found a blob of oil inside) and am nervous about getting the thing put back together correctly.

Any suggestions?

[TGTimm]

Contact your HX manufacturer now and get a full set of gaskets for your HX. Don't take it apart unless you have these--you may not need them, but if one single gasket tears when you do the break-down, you're out of business until you can replace it. Be sure you specify that you are using the HX for wort cooling, and what your CIP chemicals are, when you order the gaskets. Be sure they include the glue for attaching the gaskets.

Was this a used HX? It almost sounds to me like someone put something through it that is causing the gaskets to break down--in which case, you'll need that full set.

When I break down our HX--one of my least favorite jobs--I use the lauter tun to clean the plates, and am meticulously careful to always keep the plates in order and properly oriented--I prefer to do this with no one else in the brewery to keep distractions to a minimum. Painting diagonal stripes on the sides of the plates before break down will help to keep the order/orientation correct.

[kugeman]

Also, measure the exact depth of the HX all the way around. That way you'll know exactly how much to tighten the bolts when you put it back together.

[beerguy1]

Gotta agree with Timm. Nothing more miserable than tearing down a wort chiller. I have some concerns about using simple green I never heard of that and it has a very strong odor scares me. I use repeated water hammers to be sure and bust everything apart inside the wort chiller then its chlorinated caustic after that I leave it packed under pressure withthe caustic and then sani it on a brew day. I do occasional acid washes on it also and run the cleaning solution backwards of normal wort flow. Never had problem 1 yet and thats in 13 years. Maybe Im just too scared to open it but no sense fixing it if it aint broke

[dirtfish]

Thanks for the tips on the break down process and potential pitfalls - - I'm trying to avoid this if possible, but will use that info. to try to be prepared if we take that step.

The HX is a new Chinese sourced unit. It is has 77 plates and is a two stage configuration with clip on NBR gaskets. It's an impressive looking unit-all stainless frame. Prior to the short cycle of simple green, all that has been through either side of the HX was water, wort, caustic, acid 5, PBW and Sani-Clean-all chemicals per specified dilutions/times/temperatures. I had assumed that we did (what we thought was) adequate pre-cleaning-plus having used this for 4 brews now (that are all drainers due to some weird chemically off flavors) that we would have gotten past any manufacturing residuals or "break-in" period.

I've seen various maximum temperature specs for NBR ranging from 175F to +250F. Is it possible that the gaskets could be failing in the 180F-195F temp range and breaking down? Is NBR the typical material used for HX gaskets, or is there something different that should be used? Is this a case of poor quality imported equipment...?

[gasketman]

NBR Properties

Thanks for the tips on the break down process and potential pitfalls - - I'm trying to avoid this if possible, but will use that info. to try to be prepared if we take that step.

The HX is a new Chinese sourced unit. It is has 77 plates and is a two stage configuration with clip on NBR gaskets. It's an impressive looking unit-all stainless frame. Prior to the short cycle of simple green, all that has been through either side of the HX was water, wort, caustic, acid 5, PBW and Sani-Clean-all chemicals per specified dilutions/times/temperatures. I had assumed that we did (what we thought was) adequate pre-cleaning-plus having used this for 4 brews now (that are all drainers due to some weird chemically off flavors) that we would have gotten past any manufacturing residuals or "break-in" period.

I've seen various maximum temperature specs for NBR ranging from 175F to +250F. Is it possible that the gaskets could be failing in the 180F-195F temp range and breaking down? Is NBR the typical material used for HX gaskets, or is there something different that should be used? Is this a case of poor quality imported equipment...?

NBR (Buna) is not the preferred material for a heat exchanger. It is fine as a cheap general purpose material, but ultimately the main reason it is used in the brewing industry is more a hold-over from the dairy business. The real high temperature range for NBR is about 210F with normal service for hot liquid at 175F. There are some specialized materials that can stretch those numbers out, but you would be very unlikely to find that in an application like this. EPDM is what we generally recommend all around the brewery. It has all the resistance properties that you need for cleaning and sanitizing and the high temperature range for hot liquid and steam is 300F for a good peroxide cured material.

I hope that helps.
Dwight Clark
Jet Gasket & Seal Co

https://www.brewerygaskets.com

[morolen]

EPDM or Viton for anything that gets hot and is exposed to cleaning chemicals.

[yap]

Also, since it was a unit sourced from China, there's always the possibility that the gaskets are not made of the material that they say they are...

Just sayin'...

[dirtfish]

Yikes. I'm in contact with my equipment mfr. to try to get more specific information on the gasket material that was used.

I found that a brewery nearby has this exact HX with the same gaskets but apparently does not have the rubber smell problem.

My hot hoses are Novabrew with chlorobutyl interior rated to 240F. I'm trying to guess if anything else could be a source for this??

[TGTimm]

Oops--forgot that part about the plate pack thickness--get that from the manufacturer--it's a critical measurement.

I guess I missed the Simple Green in the OP. Man, don't go fooling around with house-hold cleaning products in your brewery! I doubt the SG was what caused your problem, but brewery cleaning chems have been developed and tested over many years of trial-and-error--why repeat that, especially the error part?

Buna rubber is a natural rubber, and definitely not what you want in an HX. I suspect this is where your problem lies--the vulcanizing (cross-bonding of the rubber polymer fibers with sulfur) of the rubber will break down with heat (and caustic cleaning chems probably don't help), which can result in exactly the kind of "rubbery smell" you describe.

Get those gaskets, and the pack thickness specs. It looks like you're gonna get to find out what an HX tear-down and rebuild is like.

Oh, yeah--wear some good cut-resistant gloves when you tear it down--those plate edges are razor-sharp (looking at the ruined knee of my pants from the last time).

[freestonebeer]

I am getting the same rubbery smell from the Hx. Only one brew fermenting from this new system and can’t speak to off flavors, but the smell alone is very odd and has me wondering.
did you ever solve this?