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View Full Version : Should I be using filtered water when caustic/acid cleaning?



Judd
08-21-2012, 10:58 AM
I'm starting to get what I can best describe as white streaks mostly in the bottom of my brite tank that look at first like residue from caustic. However they have persisted and gotten worse over a year and a half. My clean/sani procedures are as follows: Hot water rinse to get tank temp up, 170F caustic circ for 30-60 mins, hot water rinse, 140F acid circ for 15 mins, hot rinse, cool rinse, ClO2 sani circ, CO2 purge, and finally beer. This is the procedure I always follow. I have even tried scrubbing the white streaks with scotch brite and only smears the stains a little and scuffs up my beautiful tank.

So I've finally come to the conclusion that maybe because I don't use the filtered water for clean/sani and we have high mineral content here in ATX, maybe the minerals are getting cooked onto the steel during the hot caustic clean? Seems like the acid cycle should get rid of it though. Any thoughts?

Haven't seen any ill effects in any of our beers, btw.

brewmaster 2011
08-21-2012, 11:28 AM
Have you checked the ph of the acid rinse solution?

Judd
08-21-2012, 11:30 AM
Have you checked the ph of the acid rinse solution?

No, but I'm using the recommended amount for a "wash" as opposed to "rinse"

brewmaster 2011
08-21-2012, 11:35 AM
check the ph then get back to me?

Judd
08-21-2012, 11:44 AM
check the ph then get back to me?

Sure, next time I do a clean. What are you looking for?

brewmaster 2011
08-21-2012, 11:53 AM
how high the ph is will show me the buffering of the water minerals?

Judd
08-21-2012, 11:56 AM
how high the ph is will show me the buffering of the water minerals?

Wouldn't you also need to know how much acid I'm using per gallon? And the strength of the stock acid solution?

brewmaster 2011
08-21-2012, 12:08 PM
who do you buy your acid from?

Judd
08-21-2012, 02:55 PM
who do you buy your acid from?

It's Five Star Acid Cleaner #5, which is just a nitric/phosphoric blend.

BenBailey
08-22-2012, 07:15 AM
You can try to see if it is carbonate buildup by putting a few drops of concentrated acid cleaner on the white spots. If they bubble, they are most likely carbonate.
You can be getting carbonate from still having CO2 in the tank before you begin the caustic CIP, or also from the water alkalinity.

If it is the water, some cleaners handle alkaline water better than others. When I worked in ATX, we had good results with Birko Cell-R-Master, and our water was not pre-treated.
If the CO2 purge is questionable, a jumpy castle blower is a cheap way to move a ton of air into the tank.

jk_brewer
08-23-2012, 09:55 AM
We have very hard water from a well just outside of Austin and we use Loffler's Leracid KMS-10 and have never had any mineral based residue issue.

dick murton
08-27-2012, 09:18 AM
Try cold rinsing after the acid, as I have seen scale build up which I have blamed at least partially on mineral deposition when cold water comes into contact with hot metal. As previously mentioned, this may be exacerbated by having caustic going into a CO2 filled atmosphere.

What temperature is your hot caustic. I understand from our supplier that temperatures over about 65 are liable to degrade the caustic and cause precipitaion.

It does sound as though you should be using softened water as well. or at least partially softened water to reduce the precipitation risk.

gitchegumee
08-27-2012, 06:57 PM
Filtered water? Absolutely! If you're not filtering your water, it's not good for much in a brewery. Everyone should filter all of their brewery use water. Even for rinsing floors. I know that's over-generalization, but I can't think of any reason to contradict it. Who wants gunk in their water? I use a 20 micron cartridge followed by a 5 micron cartridge followed by a carbon "filter" and then a 1 micron polishing cartridge for brewing water. Washdown water is tapped from the above before the carbon "filter". Perhaps what you meant was demineralized or ion exchange or RO or some other water treatment that alters the chemical profile? That's a different animal. For that I try to get the brewing water that I need for my beers, then adjust the chemistry of my cleaning regimen to suit this water, then practice good water conservation measures. Lots of chemicals out there specifically formulated for hard water. Partner with a good chemical supplier dedicated to getting your tanks spotless and shiny without a long or expensive cleaning regimen. Your current CIP regimen is pretty intense in energy and time IMHO. You may want to look at cleaners that work well without the high heat you are currently using. Good luck!

Judd
09-14-2012, 12:06 PM
Ok, sorry it's taken a long time to respond but I have more info and pics. The problem is continuing to get worse.

First some quick responses:
I always purge CO2 before introducing caustic.
Caustic wash temp is usually 160-170F
pH of acid wash is 1.87 @1oz/gallon and 1.6 @2oz/gallon
All rinses are hot water
I put a few drops of acid on the spots and nothing happened, so i'm guessing it's not carbonate.
As you can see from one of the pics, I've scrubbed by hand with scotch brite with both caustic and acid and nothing removes it.

Looking at the pics you can see that it's basically white streaks that run down from the sides, into the dish and form a ring on the bottom...as if it is the final rinse water that is leaving something behind as it dries. Perhaps it's because I'm using a hot rinse and I should rinse with cold after the acid? As a test however, I didn't rinse at all after the last acid cycle, letting it air dry in an acidic state and what was left was even worse, more white buildup and some orange/rust streaks as well. These did wash off however. I have noticed rust-looking streaks in my fermenters as well. I don't get it.

I'm thinking of running a passivation cycle, which according to the instructions on Acid Cleaner #5 means FIVE ounces of acid PER GALLON of water. That is a shitload of acid to waste if it doesn't work. Currently I'm running a 2oz/gal 120F acid cycle in the brite for an hour to see what happens.

Sorry for the long response, any help would be appreciated.

Judd
09-14-2012, 12:10 PM
Filtered water? Absolutely! If you're not filtering your water, it's not good for much in a brewery. Everyone should filter all of their brewery use water. Even for rinsing floors. I know that's over-generalization, but I can't think of any reason to contradict it. Who wants gunk in their water? I use a 20 micron cartridge followed by a 5 micron cartridge followed by a carbon "filter" and then a 1 micron polishing cartridge for brewing water. Washdown water is tapped from the above before the carbon "filter". Perhaps what you meant was demineralized or ion exchange or RO or some other water treatment that alters the chemical profile? That's a different animal. For that I try to get the brewing water that I need for my beers, then adjust the chemistry of my cleaning regimen to suit this water, then practice good water conservation measures. Lots of chemicals out there specifically formulated for hard water. Partner with a good chemical supplier dedicated to getting your tanks spotless and shiny without a long or expensive cleaning regimen. Your current CIP regimen is pretty intense in energy and time IMHO. You may want to look at cleaners that work well without the high heat you are currently using. Good luck!

You're right, I was thinking of softened water, not filtered. Obviously carbon filtering wouldn't remove the minerals. The reason we don't use filtered for cleaning like most people do is that we don't have a HLT. So I heat water in the kettle for cleaning and running all that water through our 3 stage carbon filters will mean replacing them much more often.

Judd
09-14-2012, 01:11 PM
And the two hour, hot, double strength acid wash did absolutely nothing. :mad:

Judd
09-17-2012, 08:38 AM
Lots of views...anybody got any ideas?

Ted Briggs
09-18-2012, 07:23 AM
is your "caustic" actually PBW? If so thats your problem- switch to 5star "heavy-duty recircualtion cleaner"

Judd
09-18-2012, 09:16 AM
is your "caustic" actually PBW? If so thats your problem- switch to 5star "heavy-duty recircualtion cleaner"

Negative. 5 Star HD caustic #2

Greenbushguy
05-01-2014, 02:06 PM
Why are you using Chlorine Dioxide sanitizer in a stainless steel vessel? I don't know if I would trust it unless I knew it was pure ClO2. It could have other acidic things in it that would make it NOT good for stainless steel. That may be part of your problem. It'll destroy the protective coating on the steel and also possibly cause it to start rusting. If that's the case the only way to fix it is re-passivisation. Probably with Nitric/phosphoric acid blend. Pure Nitric acid are best for passivisation but are NASTY to use.

dick murton
05-01-2014, 11:47 PM
I suspect the white streaks are now formed from calcium phosphate, not calcium carbonate. You will therefore need to carry out a special descaling clean with something like EDTA to get rid of them. Once formed, normal formulated caustic tends not to get rid of deposits.

Check the formulation of the caustic is suitable for your hard water - it may not have enough additives in.

Stop hot rinsing with hot water. This is where a lot of the problem arises, as the CaHCO3 degrades to less soluble CaCO3 due to the heat. If the water was soft, you could quite easily get away with hot water, but why waste energy on hot water? But the water needs to be sterile.

Softened or RO treated water for CIP - definitely - to avoid a repeat of the scale formation.