Buying suitable and already diluted phosphoric acid

[Birrofilo]

While discussing rinsing of sanitization agents in another thread, it was bought to my attention by user @bu_gee that Star San and Saniclean are principally made of phosphoric acid, which is also used in brewing as an acidifying agent.

I don't know exactly about Star San, which probably contains some other ingredients besides phosphoric acid. Regarding Saniclean which I have now in my hands, the only ingredient which is declared is "Phosphoric acid 20-30%".*

The indication is vague, but it's enough to make me win my phosphoric-acid-phobia. If I can handle Saniclean without fear, I should be able to find Phosphoric acid already diluted, at 20 or 30%, and use that both for sanitization and wort acidification (or maybe only for acidification, as I see that SaniClean is not only phosphoric acid).

In brewing sites I only find this acid at 75% strenght. That requires serious precautions. I could just buy that, find a suitable plastic container, dilute it and mark it appropriately, but then again, handling those acides can be troublesome for an inexperienced person like myself: bubbling, boiling, splashing of acid, specific gloves etc. I would prefer to avoid.

I see that I can buy a product like this, at a known concentration, already diluted:
https://www.restauro-online.com/Acido-fosforico-20-puro-H3PO4
That's 1,1 kg, 1 litre, it's much cheaper than Saniclean, only €6, it's 20% so it's OK for my purposes, both sanitization and acidification, it does require caution but it's not as dangerous as 75% or 85% commonly found.

My problem is: this is not "food grade", it's meant for furniture restoration.

The question is: should I go for a "food grade" acid? Is there any risk that there is some unwanted substance inside here? Or is it just "Phosphoric acid", H3PO4, a molecule is a molecule is a molecule, should not be "food grade" or "not food grade". The seller says it is "pure".

I feel like that's my product but I would like to verify first with you.

* I see in the safety document that there are two more ingredients:
Acido (9Z)-octadecenoico, solfonato, sali di sodio (5-10%)
and 1,2-propandiolo (1-5%).

 

[bu_gee]

I would definitely look for food grade. Food grade usually means that they avoid (cheaper) production processes that could end up with toxic or dangerous sides products.

That being said, products intended for sanitization also have surfactants and pH buffers, among other chemicals that help it do its job. I don't know how vital they are, but from my experience with surfactants in cleaning fabric, I'm guessing they're pretty vital.

 

[Birrofilo]

I would definitely look for food grade. Food grade usually means that they avoid (cheaper) production processes that could end up with toxic or dangerous sides products.

That being said, products intended for sanitization also have surfactants and pH buffers, among other chemicals that help it do its job. I don't know how vital they are, but from my experience with surfactants in cleaning fabric, I'm guessing they're pretty vital.

Yes, I had already come to the conclusion that I would continue using Saniclean as a sanitizer, because it contains other substances besides phosphoric acid.

The shop gives the list of the other substances which can be found in the product, but I have no idea what to make of them, although they seem very tiny amounts. We are talking milligrams, or even micrograms, on the kilogram of acid (of which we use a few grams for an usual batch). But who knows which is the toxicity threshold of, let's say, mercury (Hg) or lead (Pb)?

I found the email of the producer in the safety sheet and I asked them whether the use I would make would make sense. I will come back here with their answer.


Specifiche garantite dal produttore:


Titolo (H3PO4) 20%
Acidi liberi (CH3COOH) max. 10 mg/kg
Nichel (Nl) max. 0,5 mg/kg
Nitrati (NaNO3) max. 2 mg/kg
Solfati (SO4) max. 115 mg/kg
Cloruri (Cl) max. 7 mg/kg
Cromo (Cr) max. 1,5 mg/kg
Vanadio (V) max. 1,0 mg/kg
Rame (Cu) max. 0,7 mg/kg
Ferro (Fe) max. 5 mg/kg
Arsenico (As) max. 1,0 mg/kg
Piombo (Pb) max. 0,3 mg/kg
Calcio (Ca) max. 10 mg/kg
Cadmio (Cd) max. 0,2 mg/kg
Fluoruri (F) max. 10 mg/kg
Mercurio (Hg) max. 1000 µg/kg
Metalli pesanti (Pb) max. 5 mg/kg

 

[day_trippr]

fwiw, I buy a 32 ounce bottle of 85% PA from Dudadiesel via their Amazon store, then dilute to 25% with my RO water, 250 MLS at a time.

 

[bu_gee]

Yes, I had already come to the conclusion that I would continue using Saniclean as a sanitizer, because it contains other substances besides phosphoric acid.

The shop gives the list of the other substances which can be found in the product, but I have no idea what to make of them, although they seem very tiny amounts. We are talking milligrams, or even micrograms, on the kilogram of acid (of which we use a few grams for an usual batch). But who knows which is the toxicity threshold of, let's say, mercury (Hg) or lead (Pb)?

I found the email of the producer in the safety sheet and I asked them whether the use I would make would make sense. I will come back here with their answer.


Specifiche garantite dal produttore:


Titolo (H3PO4) 20%
Acidi liberi (CH3COOH) max. 10 mg/kg
Nichel (Nl) max. 0,5 mg/kg
Nitrati (NaNO3) max. 2 mg/kg
Solfati (SO4) max. 115 mg/kg
Cloruri (Cl) max. 7 mg/kg
Cromo (Cr) max. 1,5 mg/kg
Vanadio (V) max. 1,0 mg/kg
Rame (Cu) max. 0,7 mg/kg
Ferro (Fe) max. 5 mg/kg
Arsenico (As) max. 1,0 mg/kg
Piombo (Pb) max. 0,3 mg/kg
Calcio (Ca) max. 10 mg/kg
Cadmio (Cd) max. 0,2 mg/kg
Fluoruri (F) max. 10 mg/kg
Mercurio (Hg) max. 1000 µg/kg
Metalli pesanti (Pb) max. 5 mg/kg

Is there a similar analysis of the Saniclean? I'm not sure that these are actual levels as much as the minimum sensitivity of their quality control process.

 

[bu_gee]

This thread from nearly a decade ago also discusses this and seems to indicate that I've been a fool.

I just did a quick search and I can get a gallon (3.78L) of 75% H3PO4 for about $40. I would prefer closer to 1 L or 500 ml, but at least it is a reference.

 

[Birrofilo]

fwiw, I buy a 32 ounce bottle of 85% PA from Dudadiesel via their Amazon store, then dilute to 25% with my RO water, 250 MLS at a time.

Is it safe to put the original strenght acid in a SS pot and add in there the water slowly? Will it corrode the pot?

I also have to find some suitable plastic to put the stuff in.

I could buy this 1 litre - 75% flask, this certainly is for food use (it's from a homebrewing supply site and it is marketed by Brewferm).
I would put this, slowly and carefully, inside a SS pot.
Then I would add two volumes of distilled water to cut it to 25% strenght.

Then I have to find three suitable containers to store the liquid.
I could just look at the plastic code on the Brewferm flask (such as PP, PET etc.) and use a flask of the same code, but I have a hunch that not all PP, or PET etc. are created equal, and that flasks that contain chemicals of this kind have some special quality that ordinary PP, PET don't have.

 

[Birrofilo]

Is there a similar analysis of the Saniclean? I'm not sure that these are actual levels as much as the minimum sensitivity of their quality control process.

I don't know. It says "guaranteed by the producer" which naturally means that the producer guarantees "no more than that". So it might be that the producer has "0" result on all those substances and he guarantees that each substance does not reach that threshold which would make the "radar" blip.

The product might be even better than what would appear.

I am surprised at the level of information which is given for a product which is sold for furniture restoration, though. It might be "food grade" at the origin.

 

[bu_gee]

Is it safe to put the original strenght acid in a SS pot and add in there the water slowly? Will it corrode the pot?

I also have to find some suitable plastic to put the stuff in.

I could buy this 1 litre - 75% flask, this certainly is for food use (it's from a homebrewing supply site and it is marketed by Brewferm).
I would put this, slowly and carefully, inside a SS pot.
Then I would add two volumes of distilled water to cut it to 25% strenght.

Then I have to find three suitable containers to store the liquid.
I could just look at the plastic code on the Brewferm flask (such as PP, PET etc.) and use a flask of the same code, but I have a hunch that not all PP, or PET etc. are created equal, and that flasks that contain chemicals of this kind have some special quality that ordinary PP, PET don't have.

Remember to always add acid to water and not the other way around. Most acid dilution reactions are exothermic so if you add water to the acid, you risk generating heat that the acid can't absorb and it can flash boil the water you add and splatter the acid.

I find that your average PET soda bottle is pretty well able to handle Star San at its mixed strength for a long period of time (>2yr). I'm not sure about stronger acid, but I'd bet it would be fine. Perhaps just try making a small amount at a time and see how it does.

I would avoid all metal containers unless it was absolutely necessary. It isn't that I know it'll be a problem, but more out of paranoia.

 

[bu_gee]

For reference, here is the certificate of analysis for the food grade phosphoric acid from Duda Diesel:

https://www.dudadiesel.com/msds/phosphoricFGCOA.pdf

From what I can tell, the amounts listed in this document are higher than the ones you've listed above. I don't really know what that means, because this document also says that this is also certified. and it does look like it is just the bare minimum limit of their quality control testing. If they detect any, it will be near or above the listed level.

 

[Birrofilo]

Remember to always add acid to water and not the other way around. Most acid dilution reactions are exothermic so if you add water to the acid, you risk generating heat that the acid can't absorb and it can flash boil the water you add and splatter the acid.

I find that your average PET soda bottle is pretty well able to handle Star San at its mixed strength for a long period of time (>2yr). I'm not sure about stronger acid, but I'd bet it would be fine. Perhaps just try making a small amount at a time and see how it does.

I would avoid all metal containers unless it was absolutely necessary. It isn't that I know it'll be a problem, but more out of paranoia.

Yes of course, I read many times that I have to add acids to water, but at 3 am I was not very bright.

I found some HDPE containers which I can use for storage. One is full of bleach which I can put in a glass bottle, the other used to contain washing-machine detergent. HDPE should be probably better also as far as permeability to oxygen is concerned.

I can make the mixture inside a non-porous terracotta pot, I think. Or I can use one of the plastic food containers. That's only temporary, but I would like not to use a porous material such as plastic.

Also, considering that I am using Phosphoric Acid only for acidification, I think I will buy the small quantity, 150ml or so, it will last years.

 

[Birrofilo]

I see fluoride value is the same for both products, while other contaminants: lead, cadmium, arsenic are way more in the Dudadiesel product than in the furniture restoration product!

Actually lead (Pb) is quoted twice in the furniture restoration product. One as Piombo (Pb) another as "heavy metals (Pb)", which are present in much higher quantity, there must be some other heavy metals, different from lead. It is possible that also the Dudadiesel product lists "heavy metals" simply as "lead". This might be a convention because Pb is the most dangerous, maybe. In any case "Heavy Metals" in the furniture restoration product is "max 5 ppm" while the Dudadiesel has lead max 3 ppm.

Dudadiesel, judging from their name, is not probably specialized in food-safe chemicals.
I suspect the furniture restoration product is fine, but I will wait for the producer's answer and I report it.

The producer might also give a "defensive" answer, though. Maybe if we ask Dudadiesel whether their phosphoric acid is suitable for beer making, they would just answer "this product is not intended for food production" because they have no food-safe certification for the product and they doesn't feel authorized to give a green light in writing, although they might say, in talk and confidentially, that it is perfectly OK.

 

[Birrofilo]

I found the datasheet for Brewferm Phosphoric acid:
https://www.brouwland.com/content/d...5.055.8-055.056.6_SPEC_EN_Phosphoric acid.pdf
The "mystery" of heavy metals (Pb) is solved, heavy metals are expressed "as lead".

All contaminants are higher or equal to the furniture restoration product.

The only value for which the Dudadiesel product is better than the two other products is the Lead (which I suppose in the Dudadiesel sheet means "Heavy metals expressed as lead").

The Brewferm product, which is certainly approved for brewing use, has the highest content of heavy metals of the lot (max 10 mg "as lead"), and a content for all other contaminants which is never less than the furniture restoration product, which appears to be overall the "cleanest" of the three.

Or actually not, if the data for the furniture restoration product is given "after dilution", because it is 20% strenght instead of 75%!

No, it is given before dilution, because the product at 75% strenght has the same data:
https://www.restauro-online.com/epages/63807438.sf/it_IT/?ObjectPath=/Shops/63807438/Products/121

 

[bu_gee]

I see fluoride value is the same for both products, while other contaminants: lead, cadmium, arsenic are way more in the Dudadiesel product than in the furniture restoration product!

Actually lead (Pb) is quoted twice in the furniture restoration product. One as Piombo (Pb) another as "heavy metals (Pb)", which are present in much higher quantity, there must be some other heavy metals, different from lead. It is possible that also the Dudadiesel product lists "heavy metals" simply as "lead". This might be a convention because Pb is the most dangerous, maybe. In any case "Heavy Metals" in the furniture restoration product is "max 5 ppm" while the Dudadiesel has lead max 3 ppm.

Dudadiesel, judging from their name, is not probably specialized in food-safe chemicals.
I suspect the furniture restoration product is fine, but I will wait for the producer's answer and I report it.

The producer might also give a "defensive" answer, though. Maybe if we ask Dudadiesel whether their phosphoric acid is suitable for beer making, they would just answer "this product is not intended for food production" because they have no food-safe certification for the product and they doesn't feel authorized to give a green light in writing, although they might say, in talk and confidentially, that it is perfectly OK.

This is food grade phosphoric acid. The NSF certification on the sheet is actually a pretty big deal in terms of food safety. Several people on the forums recommend Duda Diesel as a good source for phosphoric acid.