Sourdough Starter Jars


When I started my sourdough journey I went to my pantry and looked at the glass jars that were available. In most of the online videos I had seen the size looked in the quart range and I only had one available vessel that was about that size. It had a screw on plastic lid that was not ideal, but one uses what is on hand.

I started with 50 grams of flour and 50 grams of water and it did not take up very much room in that big jar but room to expand was plentiful. On day 2, I did not discard any and raised my mix to 200 grams total. Still swimming in this jar.

Isabel’s first home. Notice the interior shoulder at top of jar.

By day 3 I discovered the issue with most off the shelf jars for sourdough starter. The lip that contains the exterior screw threads creates a shoulder inside the jar. When pouring starter out, that shoulder is hard to scrape clean. I needed a straight sided jar. I had a few straight sided Ball caning jars but they were all too small plus the lids and rings were not exactly in pristine condition.

I had identified the Weck mold jar as the choice of the Sourdough Cognoscenti. However, in the times of Covid, this jar was not only expensive due to it’s imported nature but hard to come by as well. I did not recognize just what made it the jar of choice but it showed up in so many video kitchens.

A glass on glass lid made sense to me. Having no contact with either metal or plastic seemed a good idea for this living organism we call starter. The good old American brands Ball and Kerr wide mouth line have a straight sided interior but the lids and rings are still problematic to me.

Kilner Swing Top with wire removed

I ended up ordering a 12 oz Kilner Swing Top that seemed a better size than what I was using. The spring loaded hardware could easily be taken off and it would have the glass lid that Isabel deserved.

An aside here about starter volume. Many recipes you will see have flour volumes in the 500-800 gram range. Two loaves are the norm. Fairly large starter volumes are necessary. When I started baking bread regularly several years ago I adapted a basic recipe for one loaf that would last me a day or two and I would just make more bread. When I started with sourdough, that recipe was adapted to the new leavening method. One loaf means less flour means less starter means smaller starter vessel needed.

The Kilner jar was a good size but the lid is pretty thick to hold the wire closure mechanism. The top of the jar itself has a similar structure. This means more places for starter to get into while pouring starter from the jar. After feeding the starter the last task is to clean up the top of the jar. It is not onerous but can get annoying knowing there is a better jar design.

Kilner after pouring discard

Weck jar detail

I finally got my delivery of the Weck Mold Jar Combo Pack with 200 ml small, 500 ml medium, and 750 ml large jars with lids and rings. The top of the jars are much easier to keep clean. The small jar will be used to build a levain for one bake, the medium has become Isabel’s new home, and the large jar will be used for something or other.

As with my other jars used for starter, I added lines for volume at 50ml levels with a Sharpie Oil based Paint Marker. This marker sticks fairly well to glass and gives me easy visual volume levels. A small piece of black gaffer tape shows start volume and a rubber band for the highest rise level.

Also deserving mention is the wide mouth that comes with the tapered sides. It makes it easier to both add your ingredients and stir the contents. The lids have a close fit with the jars leaving little room to slip side to side.

There you have my treatise on the proper jar for your starter. I wrote this because other than recommending glass I had not seen the topic of jar geometry discussed.

Sourdough Starter Jar Geometry counts. Of course, I am a geek.

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