Thump Keg

Putting older posts here. Going to try to keep the novice forum pruned about 90 days work. The 'good' old stuff is going to be put into appropriate forums.

Moderator: Site Moderator

Post Reply
Godstilla
Swill Maker
Posts: 251
Joined: Wed Sep 03, 2008 3:56 pm
Location: FROM MY COLD DEAD HANDS

Thump Keg

Post by Godstilla »

I saw a pic of a still with a Mason Jar as a thump keg. Is that safe?
rustyone
Novice
Posts: 16
Joined: Mon Mar 24, 2008 5:01 pm

Re: Thump Keg

Post by rustyone »

I have seen few thumpers being glass jars also. I would have thought this would not have been ideal, as I would imagine that the thumper would eventually get hot. If I was going to use a thumper, I would lean towards a stainless steel vessel for it (cooper is just too expensive here).
eternalfrost
Trainee
Posts: 785
Joined: Fri Mar 14, 2008 4:28 pm

Re: Thump Keg

Post by eternalfrost »

if you are going to use glass at least use pyrex.

just hink about it, by design, the temp in the thumper is going to be 170-212 degrees. normal glass just isnt meant for that and the thermal shock will guarenteed break it, if not today then tommorow.

having half a gallon of high proof liquor bust all over near an open heat source is a recipe for a bad time
rad14701
retired
Posts: 20865
Joined: Wed Dec 19, 2007 4:46 pm
Location: New York, USA

Re: Thump Keg

Post by rad14701 »

While mason jars are reqularly simmered in a boiler prior to lidding as part of the canning process I would also be a bit leary of having one filled with hot ethanol dangling in close proximity to an open flame... I know it's been done, but...
eternalfrost
Trainee
Posts: 785
Joined: Fri Mar 14, 2008 4:28 pm

Re: Thump Keg

Post by eternalfrost »

rad14701 wrote:While mason jars are reqularly simmered in a boiler prior to lidding as part of the canning process I would also be a bit leary of having one filled with hot ethanol dangling in close proximity to an open flame... I know it's been done, but...
i blow glass as a hobby...
the key thing with glass is thermal shock.
all materials expand when they heat up. glass however, is an excellent thermal insulator. so temperature changes take a relativly long time to travel through it. becuase of this, if you say pour boiling water into a room temp glass, the inside will expand before the outside even gets hot. the inside expanding against the smaller outside creates huge internal stresses. glass is extremely brittle and this stress easily will crack it.

borosillicate glass (pyrex just a name brand) has a very low coefficient of thermal expansion. that is, it expands very little for a given temperature difference. this lets it withstand much greater thermal conditions then normal glass. thats why pyrex glass is used for baking dishes, scientific test tubes etc and even smoking pipes.

mason jars work fine in a boiler for canning becuase the ENTIRE jar is heated up ant a CONSTANT rate and very SLOWLY. glass can handle any temperature you want just fine. but its thermal gradients within it that will quickly shatter it.

so having the bottom half full of hot ethanol and the top exposed to air is a BAD idea.
rad14701
retired
Posts: 20865
Joined: Wed Dec 19, 2007 4:46 pm
Location: New York, USA

Re: Thump Keg

Post by rad14701 »

More or less what I was eluding to, without getting technical, eternalfrost... 8)
Post Reply