Precise duration of time.

[Jimmy Langford]

Look through the bottom of the bottle sideways, that can be your first indicator.

Oh definitely. That’s what I always do. The thick glass reveals the purple all the time. It can be quite challenging sometimes to see if a bottle is purple. The lighting means everything.

 

[Len]

Is UV light the only way it oxidizes? Digging purple bottles i have to say I don't know. Can time alone do it?
ROBBYBOBBY64.

Hi RB!
Both good questions. I read somewhere that most major bottle makers quit using manganese by about 1915.

 

[ROBBYBOBBY64]

Hi RB!
Both good questions. I read somewhere that most major bottle makers quit using manganese by about 1915.

Germany supplied a large part of the worlds manganese, it was one of the first things they stopped exporting. We needed to find a new or different source, which we did.
ROBBYBOBBY64.

 

[Len]

Anyone know if the Germans resumed sending manganese in the '20s or '30s??