[Blindtlk] more canning questions

[Julie J.]

Steve or anyone who knows about canning food,

I've been looking at canners, and all the new ones seem to have a visual 
pressure gauge.  If I'm understanding this correctly, there would be no 
hissing/rattling noise like from the older type of weighted metal pressure 
cap.  My experience with pressure cooking is very limited.  Are these newer 
models of pressure canners with the numerical gauge at all useable by blind 
people?  How will I know when it's up to pressure?  How will I know when 
it's too much pressure, preferably before the safety valve blows off. 
*smile*

If there is a particular brand and model that anyone knows of that they have 
successfully used non visually, I'd be forever appreciative of the info!

Julie