How long is caustic soda solution effective?

[imark]

Anybody got any information on this? I've made up 15L of 5% solution for cleaning stubborn grime on some bottles. How long can I keep using it?

[Will_D]

Caustic is unlikely to change over time!

It may well become diluted and have its pH changed by anything acid but caustic is caustic and stays a single compound!

Unlike Chlorine and Oxygen based products:

VWP and Bleach/Vinegar: The chlorine will come out of solution and its the chlorine that's the sanitiser

Oxybased cleaners like Lidl W5(perCarbonate) and perAcetic loose the mon-atomic oxygen very quickly. It is the O+ ion that is the sanitiser.

However your good old campden tablets are also a nice simple sanitizer that improves with age 9but again not dilution).

Campden tabs when disolved form a solution of Sulphurous Acid (H2SO3) this can oxidise to the much stronger Sulphuric Acid. This last para is a bit contentious these days but it was what I was taught!

[imark]

Thanks Will. I've a lot of grimy bottles that need soaking so several rounds on the same batch of caustic is good news.

[Hop Bomb]

Is 5% enough to do much? Its 500ml caustic in 20 litres hot water for the caustic wash with CIP.

[Will_D]

Is 5% enough to do much? Its 500ml caustic in 20 litres hot water for the caustic wash with CIP.

Now that's another question and one I don't have an answer for!

5% caustic is not nice stuff - just ask your clothes or your fingers!

Seriously tho':

You can buy some VERY dangerous chemicals in the DIY stores:

Like Solid Caustic Soda pellets and also 90 odd% conc. Sulphuric Acid (Both sold as drain cleaners)

Unless you REALLY know what ye's doing with these Beware!

[CARA]

2% is the recommended dilution rate IIRC

[Ned]

A brewery would use a solution of 3% caustic for vessel cleaning so I wouldn't worry if it got diluted a bit for bottles. If possible and you get to much sediment in caustic solution then try de-sludge the bottoms. Also protect your eyes.

[CARA]

And your hands/arms-very handily takes a layer of skin off

[imark]

OUCH! 

[Hop Bomb]

That looks nasty. Where are your gloves & goggles?

Is brewers caustic & caustic soda different? 500ml brewers caustic per 20 litres here. 4 to 5 of those buckets to a 2000L tank for the caustic wash.

[Blueshed]

Thanks Will. I've a lot of grimy bottles that need soaking so several rounds on the same batch of caustic is good news.

you need some bottles, i could drop you down 30+ brown 500ml btls, all nice n clean.

[imark]

Thanks for the offer but I've loads of them. The ones I'm scrubbing are my heavy gueuze bottles.

[imark]

Yeah. They're the ones alright. Labels are a bitch to get off.

[Damien M]

Yeah. They're the ones alright. Labels are a bitch to get off.

After a soak I use a stanley knife and plane off the label and glue in strips it works a treat. Sometimes it even works better on a dry label (gypsy labels particulary)