Ask The Brewmasters

hello,

I have a tank in my brewery that appears to be showing signs of having a glycol leak. In the past 2 weeks I had began to notice puddles under a specific BBT. I went and tightened the glycol connections at the top to make sure there weren't any leaks there. After that I topped up our chiller.

This morning there was another puddle under the BBT. I can confirm it is glycol, and from what I can tell it appears to be leaking out of the legs. Each tank leg is on a stainless steel pad, and somehow there is a puddle on each of the four pads despite the water on the floor not being high enough to get over the lip.

The beer inside the tank doesn't show any signs of being contaminated with glycol. Gravity readings have been consistent since fermentation ended.

How would I go about confirming where the leak is on my tank?

Thanks for any help.

Cheers

------------------------------
Matt Lyons
Head Brewer
Trestle Brewing Co
Parry Sound ON
(705) 751-9108
------------------------------

Hi Matt, 

You could try using a dye on your glycol supply to make it easier to see where the leak is coming from. My initial thoughts are that if you didn't notice any leaks on the glycol piping/connections themselves, you most likely have a small crack(s) in a weld to the glycol jacket. 

Best, 

------------------------------
Patrick McMahon
Head Brewer
Castle Danger Brewery
patrick@castledangerbrewery.com
218-830-0629
------------------------------

Matt,

Something else to rule out - check any glycol piping that may be running overhead.  We ended up finding a small crack in a fitting on the glycol piping that was suspended from the ceiling over top of the tanks that was dripping down onto the tank and then just tracking on the outside of the tank down the legs to the floor and pooling at the feet.  It drove me crazy for a few days until we figured it out because all the glycol piping connections on the tank were tight and had no signs of leaking so we couldn't figure out where it was coming from.  

------------------------------
Moriah Guise
On-Site Production Manager
Levante Brewing Co
West Chester PA
(615) 972-8252
------------------------------

Hi Matt,

A few breweries ago I came into this situation.  We were able to zero into a leak with good results.  Assuming the tank is dimple jacketed with a layer of insulation and a stainless skin over it, you can get an idea of where the leak is using an IR thermometer.  Walk / squeeze around the tank slowly scanning the surface temp from top to bottom.  You should see a patch of cold show up.  A more rudimentary, but visual approach could be to run a significant amount of hot water on the floor under the tank to see where the condensation shows up.  When cutting into the skin of the tank aim high. 

Good luck.   

------------------------------
Dan Peterson
Brewmaster
Ferment Brewing Co
Hood River, Oregon
------------------------------

Hi Matt,

One of the most common locations where this type of leak occurs is where a glycol inlet or outlet nozzles welds to the heat transfer surface (see sketchy sketch below).  Thermal expansion (for nozzles welded to the out jacket), vertical loads from piping, and applied torque from a pipe wrench without proper backing are three common causes.  Depending on the size of the leak, you can drain glycol from the tank in question, apply air pressure to the jacket (don't exceed the design pressure), and use a stethoscope to locate the location of the leak.  Temperature guns do work if the leak is big enough, but small leaks are often hard to locate based on temperature.  The good thing about air leaks is that they are noisy and the stethoscope method usually works for even small leaks.

Once the leak is located, your outer jacket will likely need to be cut to allow access to the problem area.  A good repair person will be able to patch the incision with an escutcheon that should not look terrible.

Determining the root cause is important because this sort of failure can occur on multiple tanks if the cause is related to how pipes are installed or thermal expansion.  The latter problem is especially problematic on larger tanks (greater than about 200 BBLs) that have welds connecting the glycol nozzle to the outer jacket where hot CIP is used.  When the inner tank is heated, it elongates.  Because the outer jacket is at room temperature, the weld connecting the glycol nozzle to the heat transfer surface/box header is stressed and fails given enough of these cycles.

If I were to wager a bet, this is where I would place my marker!

Cheers,
Ashton

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

Thank you for all of the replies. 

Shortly after I started this thread I contacted a local to our pub who is an engineer and works in the dairy industry. He gave me this reply exactly as to where the issue most likely occurred. We have 2 inlets to our tank, so we also did the following to help figure out where the leak is.

1. Mix food safe red and green die with water
2. We filled the top jacket with a red die and bottom with green.
3. Then we pressurized the jackets to 5 psi and left them over night
4. in the morning we came in to see which dye was on the ground

We are currently waiting for a welder to come in next week and cut open the outside wall of the tank. Just went over our old drawings and hopefully they are correct, so it will be a little easier to find the appropriate inlets without too much work.  In the meantime I have also started working on getting a new BBT just in case this doesn't workout.

Cheers

------------------------------
Matt Lyons
Head Brewer
Trestle Brewing Co
Parry Sound ON
(705) 751-9108
------------------------------

Original Message:
Sent: 11-21-2024 18:25
From: Ashton Lewis
Subject: Glycol potentially leaking from BBT

Hi Matt,

One of the most common locations where this type of leak occurs is where a glycol inlet or outlet nozzles welds to the heat transfer surface (see sketchy sketch below).  Thermal expansion (for nozzles welded to the out jacket), vertical loads from piping, and applied torque from a pipe wrench without proper backing are three common causes.  Depending on the size of the leak, you can drain glycol from the tank in question, apply air pressure to the jacket (don't exceed the design pressure), and use a stethoscope to locate the location of the leak.  Temperature guns do work if the leak is big enough, but small leaks are often hard to locate based on temperature.  The good thing about air leaks is that they are noisy and the stethoscope method usually works for even small leaks.

Once the leak is located, your outer jacket will likely need to be cut to allow access to the problem area.  A good repair person will be able to patch the incision with an escutcheon that should not look terrible.

Determining the root cause is important because this sort of failure can occur on multiple tanks if the cause is related to how pipes are installed or thermal expansion.  The latter problem is especially problematic on larger tanks (greater than about 200 BBLs) that have welds connecting the glycol nozzle to the outer jacket where hot CIP is used.  When the inner tank is heated, it elongates.  Because the outer jacket is at room temperature, the weld connecting the glycol nozzle to the heat transfer surface/box header is stressed and fails given enough of these cycles.

If I were to wager a bet, this is where I would place my marker!

Cheers,
Ashton

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

I was going to say to add regular food coloring from the grocery store. It's considered food safe. Hopefully I don't have any leaking tanks in our future, but thanks for the post for troubleshooting ideas.

------------------------------
Mitchell Coolidge
Maintenance Manager
Fernie Brewing Co
Fernie BC
------------------------------

Original Message:
Sent: 11-25-2024 08:18
From: Matt Lyons
Subject: Glycol potentially leaking from BBT

Thank you for all of the replies. 

Shortly after I started this thread I contacted a local to our pub who is an engineer and works in the dairy industry. He gave me this reply exactly as to where the issue most likely occurred. We have 2 inlets to our tank, so we also did the following to help figure out where the leak is.

1. Mix food safe red and green die with water
2. We filled the top jacket with a red die and bottom with green.
3. Then we pressurized the jackets to 5 psi and left them over night
4. in the morning we came in to see which dye was on the ground

We are currently waiting for a welder to come in next week and cut open the outside wall of the tank. Just went over our old drawings and hopefully they are correct, so it will be a little easier to find the appropriate inlets without too much work.  In the meantime I have also started working on getting a new BBT just in case this doesn't workout.

Cheers

------------------------------
Matt Lyons
Head Brewer
Trestle Brewing Co
Parry Sound ON
(705) 751-9108
------------------------------


Original Message:
Sent: 11-21-2024 18:25
From: Ashton Lewis
Subject: Glycol potentially leaking from BBT

Hi Matt,

One of the most common locations where this type of leak occurs is where a glycol inlet or outlet nozzles welds to the heat transfer surface (see sketchy sketch below).  Thermal expansion (for nozzles welded to the out jacket), vertical loads from piping, and applied torque from a pipe wrench without proper backing are three common causes.  Depending on the size of the leak, you can drain glycol from the tank in question, apply air pressure to the jacket (don't exceed the design pressure), and use a stethoscope to locate the location of the leak.  Temperature guns do work if the leak is big enough, but small leaks are often hard to locate based on temperature.  The good thing about air leaks is that they are noisy and the stethoscope method usually works for even small leaks.

Once the leak is located, your outer jacket will likely need to be cut to allow access to the problem area.  A good repair person will be able to patch the incision with an escutcheon that should not look terrible.

Determining the root cause is important because this sort of failure can occur on multiple tanks if the cause is related to how pipes are installed or thermal expansion.  The latter problem is especially problematic on larger tanks (greater than about 200 BBLs) that have welds connecting the glycol nozzle to the outer jacket where hot CIP is used.  When the inner tank is heated, it elongates.  Because the outer jacket is at room temperature, the weld connecting the glycol nozzle to the heat transfer surface/box header is stressed and fails given enough of these cycles.

If I were to wager a bet, this is where I would place my marker!

Cheers,
Ashton

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337