Does PBW lose its effectiveness over time?

[Truman42]

Howdy brewers. Ive got some PBW in a container which is over 12 months old possibly older. (Havent brewed since April last year.)
I used it the other day and noticed that it didn't produce any foam or bubbles like it normally would. The water went cloudy but that was it.

Does this stuff lose its power with age?

 

[MHB]

Another resounding "Maybe"
PBW is a blend of several chemicals but mostly Sodium Metasilicate and Sodium Percarbonate. Its the latter that would be the issue.
Perk granules are available in several forms, the better ones are coated with sodium silicate to prevent or reduce the reaction with atmospheric moisture that will degrade the Perk. Given long enough any form of Perk is going to degrade.
The quality of the container the amount of moisture and the choice of granules (coated or not) will all work together to determine how long the perk will remain active.
It will still be a fine cleaner, but may have lost the ability to form peroxide so have lost its ability to sanitise.

Put a tea spoon in a glass, pour on some boiling water, if no/few bubbles/fizzing it wouldn't be safe to trust as a sanitiser.
At worst use it for cleaning and find some other sanitiser.
Mark

 

[Truman42]

I never use PBW as a sanitised anyway, always just as a cleaner.

Interesting you say that the perc is the one that will degrade as it does look like when you mix sod met with water only. (I did this once when I had some sod met left over after a bulk buy and forgot it wasnt mixed with sod perc.)

So if its okay to use as a cleaner still then Ill keep doing that and just make sure I star san anything I need sanitised.

Cheers MHB

 

[MHB]

Just a note, Metabisulphite and Metasilicate are very different beasts.
Just, with the abbreviations, to be sure we are on the same page.
Mark

 

[Truman42]

Just a note, Metabisulphite and Metasilicate are very different beasts.
Just, with the abbreviations, to be sure we are on the same page.
Mark

Yeah I was talking about Sodium Metasilicate and Sodium Percarbonate. Ive never had or used metabisulphite.

 

[dr K]

Truman42 you are a lucky man indeed if you have never used Sodium Metabisulphite. It is (or was) a common sanitiser in wineries and its cheap. What is great for wine may not be great for beer, especially at home brew sizing. Back in the dark ages it was sold as a sanitiser, great if you do not mind sulphur in your beer and pretty screwed if you are, as I am, an asthmatic.
Sodium Metasilcate in a liquid form is waterglass, you may remember growing copper sulphate crystal towers in it . Oh beer wise it is highly alkaline (though not caustc according to 5 Star) and a brilliant cleanser.

K

 

[Morrie]

How does PBW compare in price compared to sodium percarbonate? I've been using perc and I have very highly mineralised water. If I leave a solution soaking in anything for a period of time(usually 24 hrs is enough) then the calcium precipitates out of my water and sticks onto the side of my vessel I'm trying to clean. The calcium then is almost impossible to remove as its stuck on really hard. Just wondering if PBW would be a better alternative for me, but then as MHB mentions it contains perc also. I try not to soak my FV, brew kettle etc in perc for too long so this doesn't occur.

 

[wide eyed and legless]

Sodium percarbonate is unstable, it has to be kept out of sunlight in a cool dark place, an alternative is sodium perborate which is stable. I didn't know this until I went recently to buy a new bag of perc and the chemist explained it to me.