expiry date

[RyeGuy]

I have a couple of tins of Cooper's Pilsner from about 5 years ago...I realize that the yeast would probably be dead but would the extract be any good anymore?....Just wondering what I should do with these 2 tins...Just chuck em out or are they still usuable...

thanks.

[zook37]

I have used a few tins of brew well past the use by date, One was about three years past, used new yeast and they worked out fine!

[lethaldog]

As far as i know they will be a little darker than new ones, deffinately replace the yeast though

[Chris]

Yeah, the malt tends to darken over time. As for the yeast, I wouldn't use kit yeast anyway. It should be ok, but replacing it removes all doubt.

[Ed]

The tins, like any other tinned food product, have a thin inner coating protecting them from the acid environment of the foodstuff. Does this become permeable and degrade with age? Why do they have an expiry date? Every tasted a tinned product that tastes "tinny"? Personally I wouldn't use them but the choice is yours. They should still be sanitary, but what of the taste they may impart to the brew.

Cheers, Ed

[Chris]

The expiry date on the can is more to do with the yeast than the malt. It's a matter of playing the odds.

[velophile]

I bought a pile of out of date Toohey kits early last year. Some of the oldest had tiny spots of rust on the inside seams of the can. I used them all for dark styles & didn't notice any off tastes.

I wouldn't like to be making pale beers with subtle flavours with old cans. They are good for starters, just boil up a bit & keep the rest covered in the fridge or freezer.

[KEG]

as long as the tins are still intact inside, i'd say the biggest difference would be the malt darkening a bit, and the softer hop flavours disappearing. i don't think any of the bitterness would disappear, but you could definitely do with adding some aroma/flavour hops to a short boil.

[Ed]

If the malt does darken with time, then a reaction has taken place

Cheers, Ed

[KEG]

are you saying that the reaction would have happened between the malt and the tin? because the malt will darken by itself over time regardless of what container it's in, especially if ambient temperatures go up a bit every now and then.

[rwh]

Sounds to me like the sugars are slowly breaking down over time. Perhaps a similar reaction as that that occurs when making dark red Belgian candy sugar, or how the malt darkens over the length of a boil...

[Ed]

KEG, what I was trying to illustrate is if changes are noticed, then the malt is no longer the same as it once was intended to be.

Cheers, Ed

[chris.]

KEG, what I was trying to illustrate is if changes are noticed, then the malt is no longer the same as it once was intended to be.

Cheers, Ed

I agree with you Ed. The colour is not the only factor affected.
I also vaguely remember hearing that the low pH of the malt can leech the tin like flavours from the metal over extended periods?.

Sounds to me like the sugars are slowly breaking down over time. Perhaps a similar reaction as that that occurs when making dark red Belgian candy sugar, or how the malt darkens over the length of a boil...

I'm not sure that the darkening has anything to do with the Maillard Reaction (http://en.wikipedia.org/wiki/Maillard_reaction). I could be wrong though.

[Ed]

I also vaguely remember hearing that the low pH of the malt can leech the tin like flavours from the metal over extended periods?.

Yup, and I got the same info from someone industry involved with canned products. Apparently the inside coating of the tin is a just a very thin acrylic, but I haven't actually confirmed this for myself. It's meant to protect the acidic foodstuff from reacting with the tin. This is apparently why you shouldn't buy dented tins because that protective layer might have been weakened.

Cheers, Ed

[ryan]

And so it`s over to drsmurto the scientist to settle this one.
drsmurto?

[drsmurto]

Sigh. Glad to know my place in the world........

You can keep dried malt extracts indefinitely if sealed and stored in the dark and the colour wont/shouldnt change whereas you have said on this thread that the liquid stuff does. The difference between the 2 is therefore part of the reason for this. Whats the difference? The liquid extract still has some water in the tin. So the water present must accelerate the 'reaction' that is taking place.

Malt extract has a pH of approx 4 so over time this may cause some problems for lining inside the tin. Slighlty acidic solutions are more than capable of reacting with elemental tin but thats not what tin cans are made of.

Meeting to go to but will be back with more thoughts soon. Feel free to tear chunks out of these ramblings of a mad scientist.

Cheers
DrSmurto

[ryan]

Sigh. Glad to know my place in the world........

You can keep dried malt extracts indefinitely if sealed and stored in the dark and the colour wont/shouldnt change whereas you have said on this thread that the liquid stuff does. The difference between the 2 is therefore part of the reason for this. Whats the difference? The liquid extract still has some water in the tin. So the water present must accelerate the 'reaction' that is taking place.

Malt extract has a pH of approx 4 so over time this may cause some problems for lining inside the tin. Slighlty acidic solutions are more than capable of reacting with elemental tin but thats not what tin cans are made of.

Meeting to go to but will be back with more thoughts soon. Feel free to tear chunks out of these ramblings of a mad scientist.

Cheers
DrSmurto

Thank you dr. That should put them back in their respective boxes.

[chris.]

Thank you dr. That should put them back in their respective boxes.

What box?

[ryan]

You know..... the boxes
double

[chris.]

No. I'm sorry I don't