If your vat's not spotless, your milk won' t be either.
Your vat is the last stop before the tanker. If it's not clean, nothing else you've done matters. Vats are involved in around 1 in 4 hygiene grades, and usually it's because of something that looks "clean enough" but isn't.
The Real Risk of Protein Build-Up
It's not what you can see. It's what you miss.
Most vat-related grades come from protein deposits - a stubborn, thin film that clings to stainless steel like burnt milk on a saucepan. It's tough to spot, especially when the vat's wet.
Signs of protein build-up:
• Rainbow sheen or brown tint when the vat's dry
• Slippery surface even after a wash
• Thermoduric grades popping up for no clear reason
Why it matters:
Protein feeds thermoduric bacteria, the kind that survive pasteurisation and give the factories nightmares.
Common Trouble Spots and How to Clean Them
You don't need a microbiology degree to sort your vat, just a good eye and better routines.
Trouble spots:
• Inside walls and floor- protein film often forms here
• Paddle & under the stirrer- sludge loves to hide here
• "O" rings, seals, and valves - especially in bottom-fill or 3-way valve setups
• Lids and gaskets - often overlooked, but easy soil traps
Cleaning fixes:
• Use hot alkali washes with good contact time (minimum 8 minutes)
• Wash with cold acid to remove alkali residue
• If manual scrubbing is your only option - be careful. It's dangerous, unpleasant, and
not OSH-approved
Vat Clean – Manual vs Auto vs Recirculation
Not all cleaning systems are created equal. Here's how they stack up:
Method
Pros
Cons
Manual Scrub
Cheap and thorough (if done well)
Dangerous, inconsistent, OSH risk
Auto (single pass)
Easy and hands-off
Often gives <90 secs of hot contact
Recirculation
Best of both worlds. Long contact, no risk
Needs setup, but most systems can handle it
A little-known fact:
If your vat is getting two alkali washes a week with just 80 seconds contact each time, that's less than 30 seconds of proper cleaning per week.
Want to quadruple your cleaning power at no extra cost? Start recirculating. Most vat wash systems can be tweaked to do it.
Dry & Light is Your Friend
The only way to properly inspect a vat is when it's dry and in good light. Night pickups make this tricky, which means things can go unnoticed for too long.
Pro Tip: Schedule regular daytime checks, especially if you're getting alerts or unexplained grades.
Bottom Line
If you're chasing down hygiene grades and ignoring your vat, you're probably wasting time. Start your inspection at the end of the line.