Silex Science

This 1951 Silex syphon coffee maker joined the collection this past weekend.  I got it for 50% off at $5, plus the estate sale cashier threw in the rest of my items (mostly ephemera) for free, so I was happy.

The pot and bowl are made by Pyrex.  Based on what research I was able to do, it appears that both Pyrex and Silex were owned by Corning, so that would make sense.

The pot appeared to be used very little. The original instructions were still with it.

As I do with all coffee pots, I first ran it through a cycle of water and vinegar, even though this pot is mainly glass and shouldn't hold any odors.  This pot is not electric and is designed to be used on your gas or electric range. While going through the cleaning cycle, once the water syphoned to the top (I'll show that later), the whole pot and bowl tipped over spilling all of the water/vinegar on my stove, flooding the burners, etc.  What I found was the grates on my gas stove are too wide to support the bottom of the pot and once the water syphoned to the top bowl, it became top-heavy and tipped.  After that, I used an additional grate on top of my range.

To make the coffee, you first boil the water in the pot without the syphon bowl attached.

There's a spring filter attachment that uses a cloth filter (these are replaceable and instructions indicate to replace after every few pots. I didn't have any, so I boldly used the one that came with it.  Hey, it was boiled in the water/vinegar mixture too).  The rod goes down the stem of the bowl and clips on at the bottom to hold it in place.

Then, add your coffee to the bowl. It's a little awkward since you have to do this before you attach it to the pot.

The instructions say, once the water "bubbles actively", attach the syphon bowl to the pot.  I found it works fine once the water has just small bubbles coming up from the bottom of the pot regularly.  When I ran the water/vineger through the pot, I waited until it was a  rolling bowl before attaching the syphon which caused the water to rocket up the syphon into the top bowl, contributing to the chaos that ensued.

Once attached, water begins to rise into the top bowl, displaced by the steam in the pot.

The instructions indicate to stir the top bowl with a spoon to mix.

Once the water rises to the top bowl (some will remain in the pot), reduce the flame and allow to continue bubbling for a minute or 2, depending on how dark you want the coffee.  I found one minute to be perfect.

Turn off the flame when brewing is complete and the water will slowly descend back to the pot.

It made a very good cup of coffee.

Due to the long duration for boiling the water and the complexities involved, I probably won't use this pot very often, but it is a fun little science experiment.