Phosphoric Acid Dilution?

[johnno]

I have got some Phosphoric acid and intend to start using it. I am not sure of how much to dilute it though.
I have had a look at Sosman's brewiki site and the recommendation is 0.5%.
Does this mean half a ml per litre? Or am I reading it wrong?
Thanks in advance brewers.

cheers

johnno

 

[Gulf Brewery]

Hi Johnno

What are you going to do with the acid? Adjust your pH or something else?

Cheers
Pedro

 

[johnno]

Hi Pedro,
I'm going to use it for sanitising and not having to rinse.
Adjusting the PH is too scientific for me.

cheers

 

[sosman]

Funny you should ask, I did some tests last weekend so after I saw your question I went back and updated it. In summary:

-Assuming a target solution of pH 2 (apparently required for effective sanitation).
-Phos acid concentrate is 85% (about the highest you can buy it)
-20g in 10 litres gives you just under pH 2, or 2g/L. 2g of phos acid is roughly 1.3 ml

This is a little above the 0.5ml per L I mentioned http://brewiki.org/CleaningAndSanitation

At the end of the day there is probably no magical pH figure, it is also presumably dependant on contact time.

HTH

 

[johnno]

Thanks for the answer sosman.
Pedro I didn't even know you could use it to adjust the PH with this acid, thats why I didnt specify what I was going to do with it.
I just thought you only used it to clean with. :blink:

cheers
johnno

 

[Gulf Brewery]

Johnno

A few of us (in Adelaide, anyhow), adjust the pH of our mash and sparge liquor to be around the 6 mark.
We aim for a mash pH of 5.2 - 5.5 which will vary dependent on the grains, especially with dark grains. The lower sparge pH prevents tannings being extracted.

I have never used phosphoric by itself for santising. We use Dairy Power Defenter which is phosphoric acid based and includes a surfactant so that it is more effective.

Cheers
Pedro

 

[johnno]

I have never used phosphoric by itself for santising. We use Dairy Power Defenter which is phosphoric acid based and includes a surfactant so that it is more effective.

Pedro,
I was under the impression that you could just use the phosphoric acid by itself.
Is this not correct? A surfuctant is just some soap isnt it?
I suppose I can always mix it in with some dishwashing liquid but I wouldnt know what the breakdown would be.
They did try to sell me some other stuff in that place for half the price.
The lady went out the back for a while and spoke to the "boss". When she came back s esaid he recommended the other stuff. I asked to speak to him but he had taken off by then.
So whats the consensus? Can you or can you not use Orthophosphoric acid on its own.
Thanks brewers.

cheers
johnno

 

[Duff]

Johhno,

Be careful handling the acid, we use it here at the university and is always one to be used in the fume cabinet. When pouring, ensure there is plenty of ventilation around

BTW I'm sure you know the general pH scale, if you are looking to lower pH it works as a log scale, pH 5 is 10 times more acidic than pH 6, pH 4 is 100 times more acidic, etc. If you are looking to raise pH use hydroxides (OH-).

All the best - Duff.

 

[johnno]

Johhno,

Be careful handling the acid, we use it here at the university and is always one to be used in the fume cabinet. When pouring, ensure there is plenty of ventilation around

Thanks Duff,
The way this is going I'll be sticking to what I know best.
Bleach.

cheers
johnno

 

[Gulf Brewery]

Johhno

The way I undestand it is that the surfactant makes it work more effectively. Dilute phosphoric will still work from what I understand.

Anyone else want to add something to this?

Cheers
Pedro

 

[sosman]

The way I undestand it is that the surfactant makes it work more effectively. Dilute phosphoric will still work from what I understand.

Anyone else want to add something to this?

I can say two things about adding surfactant (like LABSA):

1) From experience, it helps wet surfaces. That means it sticks to surfaces that water normally runs straight off and gets in to cracks. If you want to satisfy yourself, shake up some clean water in a PET bottle, the drips all run straight to the bottom. Add a drop of detergent and a film covers the inside.

2) I have heard that the surfactant somehow jiggers the skin of bacteria (maybe just the wetting effect mentioned earlier) so that the phos acid is more effective.

FWIW - rarely fill a keg or fermenter with phos acid, I just put a couple of litres in the bottom with some LABSA and shake it. I repeat this whenever I remember.

I also pump weak phos acid through my CFC to clean it and sanitize it but I don't leave it in there.

cheers

 

[sosman]

Oh yes and there is nothing magic (at least as far as I know) with the combination of surfactant with phos acid. It can be used wherever you want some wetting effect.

Eg adding some surfactant to roundup (some brands already have some) makes it wet the leaves of the plants rather than just drip off onto the ground below.

 

[sosman]

Johhno,

Be careful handling the acid, we use it here at the university and is always one to be used in the fume cabinet. When pouring, ensure there is plenty of ventilation around

Thanks Duff,
The way this is going I'll be sticking to what I know best.
Bleach.

Johnno,

Bleach is a great sanitiser, its just that for me, having to rinse it off is a real pain. Phosphoric acid, among other things, also happens to be a yeast nutrient.

Also bear in mind that bleach is a dangerous substance, it also requires adequate ventilation, check out the MSDS for both materials if you want more info.

cheers

 

[Gulf Brewery]

sosman (of the 3 consecutive replies).

I think you hit the nail on the head when you said a surfactant was a wetting agent (Darren will nail me if I am wrong) and will assist all sanitisers in working effectively (not just phos acid)

Pedro

 

[Duff]

Surfactant (wetting agent, etc.) as sosman has said makes the leaves wet, this is due to surfactants breaking down the surface tension of the water droplet causing it to spread evenly.

In a nutshell, as Pedro has said, don't be afraid of the acid + surfactant. We all use surfactants every day as they are part of washing up detergent, included to help the detergent spread evenly over the dishes. Just handle the acid carefully.

Duff.

Off topic - dishwashing detergent is a cheap way to help with the dry areas on your lawns. Don't be afraid of the neighbours giving you funny looks as you wander around the yard squirting Sunlight on the dry spots, in a short time you'll have the best lawn in town, minus bulk amounts of water

 

[dicko]

Hi Johnno,
With all respects to the above input and the need to use caution when handling any acid or alkali, what I do is mix 10ml of phosphoric acid ( marine clean) with 1 litre of clean water (rain) and a drop or two( no more ) of Morning Fresh dish washing liquid.
It works fine for me and without problems.
I guess it is not "one shot " or whatever else there is on the market but it works and it is low cost.
Cheers

 

[johnno]

Thanks for all the answers brewers,
They have been very helpful.
I do want to get into using something you dont have to rinse. And I will go ahead with using this stuff.
Dicko espescially you have answered my question about the surfactant and how much to use.
But there is a difference in the amount you use and the amount Sosman uses.
Sosman you says 1.3 ml/L and Dicko 10ml/L.
Presuming I got this from the same place as SOsman I should go with that I suppose.
Another question I have is how many times if any can this solution be reused?
Can you leave it in a bucket for a few days like you can a bleach solution etc.

cheers
johnno

 

[dicko]

Johnno,

I use 10 ml because it is too hard to measure 1.3ml. I guess mine is a lot more acidic.
I dont bother to store mine as it is very cheap on the scale of things but I feel you could if you wanted to.
When I have soaked brewing eqipment long term in "one shot" I have found that everything in the bucket goes "slimey" and I have had to rinse it anyway.
For this reason all my long term soaking is still done with non scented "white king" in water.
This is only my preference and in no way should this influence anyones decision about one shot or phosphoric acid mixes.

Cheers

 

[sosman]

Johnno, as Dicko says, phos acid solution is cheap so there is not much point using it over and over. Furthermore if you put stuff in there that is dirty then the solution is going to get dirty.

But to answer your question, it is not like bleach or sodium met, ie it does not go off or lose its potency. I have kept clean solutions around for months.

And don't keep it in PET bottles.

 

[pint of lager]

Dicko, just to clarify, when you are long term soaking in bleach solution, bleach looses it's effectiveness over a few days made up and sitting in a bucket.

To measure out small amounts, use a syringe.

Don't forget, when mixing strong chemicals, add the acid to the water, not the other way around.