Acid Etching Your Brew Pot

Here’s a simple project that has huge bang for the buck in enhancing your life. As usual, when looking for brewing equipment, I scoured Craigslist for a good deal. As usual, the community didn’t let me down and I scored a 5 gallon steel pot for $25. Yay! The down side was that this pot had no volume graduations, leaving me to measure my water, liter by liter with a measuring cup. Oh, the humanity!

This task got old fast and I sought a solution in science. This solution came in the form of acid etching. Yes, my mastery over the natural world allowed me to enslave electrons to do my bidding, carrying metal ions away from my pot into oblivion. Perhaps it wasn’t so dramatic, but it sure worked and this Fermentologist doesn’t have to measure water anymore.

Materials:

  • Brew kettle
  • Measuring cup
  • Water
  • Electrical tape
  • Razor blade
  • 4% white vinegar
  • 2 electrical wires (speaker wire or any small gauge wire works)
  • Table salt
  • 9V battery

Step 1 – Volume Measurements

The whole point of this little venture is to have an permanently and accurately marked brew kettle so the liquid measurement is of utmost importance. Using a graduated vessel of your choice (I used a 1L glass measuring cup), fill the kettle with known volumes of water. Have the kettle sitting level and allow the water to stop sloshing before applying a piece of electrical tape in line with the water level at each desired volume.

Step 2 – Kettle Prep

As with all facets of brewing, cleanliness is key. The brew kettle must be cleaned thoroughly and any residue of cleaning agent must be washed away. There is no voodoo to this step, dish soap does the trick just fine. Next, the kettle need to be dry for application of the stencil.

Step 3 – Applying Numbers and Graduation Lines

There are many commercially available stencil options available from your local craft store or ebay. Being a thrifty fellow, I opted to create my own stencil freehand with electrical tape and a razor blade. Although this was inexpensive and fun, I don’t recommend it unless you (like me) prefer function over fashion and don’t give a toss that it looks like it was etched by a drunken three year old.

Etching materials with brew kettle
As you can see from the level beer in my glass, the whole stencil process took about 20 minutes

I stuck pieces of electrical tape to a piece of plywood and “drew” the numbers and lines with my razor blade. The zeros and eights were the hardest as they needed separate little dots (mine were square, because I’m lazy) in the centre of the circles. The stencils were then carefully peeled away from the plywood and stuck to the appropriate places on the inside of the kettle.

Electrical tape stenciled number

Step 4 – Etching

Caution! The etching process creates a small amount of toxic chlorine gas, do this in a well ventilated area!

It’s time to commit to your stencil design and make it permanent. You’ll need a source of ions to exchange with the stainless steel, this comes in the form of white vinegar with table salt (acetic acid with sodium chloride, if we’re going to be technical). Dissolve 1/2 teaspoon of salt into about 20mL of vinegar. Next, connect one piece of wire to the pot using electrical tape. Connect the other end to the positive terminal on a 9V battery. The second wire gets connected to the cottony end of a Q-Tip. It’s tricky to get it to stay put so wrap it around the Q-Tip and try to embed the wire into the cotton. Dip the Q-Tip into the vinegar solution and press it against the side of the container to squeeze out excess vinegar.

Vinegar solution with Q-Tip and battery

Finally connect the other end of the Q-Tip wire to the negative terminal on the 9V battery. With a piece of electrical tape, secure the wires to the battery and press down on them to make good contact while etching. Begin tracing your stencil, taking care to stay within the lines. You should hear sizzling and see small bubbles and a colour change where you put the Q-Tip. The Q-Tip will turn brown and depending how much area you are etching, you may need to use multiple Q-Tips. Continue etching until the colour change is uniform throughout.

Step 5 – Cleanup

Etched numbers inside brew kettle
Not my best work, but it was a learning experience

You’re done! Ensure that all areas were etched uniformly and then peel away the stencils. You should see beautiful, time-saving numbering on the wall of your kettle. All that is left is to give it a wash with soapy water and then take it for a test drive on your next brewing adventure.

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