Have you checked the ph of the acid rinse solution?
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.
Last edited by Judd; 09-17-2012 at 12:57 PM.
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"Originally Posted by brewmaster 2011
check the ph then get back to me?
Sure, next time I do a clean. What are you looking for?Originally Posted by brewmaster 2011
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?Originally Posted by brewmaster 2011
who do you buy your acid from?
It's Five Star Acid Cleaner #5, which is just a nitric/phosphoric blend.Originally Posted by brewmaster 2011
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.
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.
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.
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!
Palau Brewing Company
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.
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.Originally Posted by gitchegumee