While it is possible to brew without the simplest of measurements, a key to repeatable recipes is measuring your ingredients. Your grain and hops may come pre-measured, but you still need to know how much water you’re using and how much wort is in your pot. I’ve gotten by for several years using a notched yardstick, and one of my kettles has a sight glass, but when I read an article about etching volume markers on a stainless steel kettle, I got excited—it sounded cheap and easy, I’d have one less piece of equipment to hassle with, and, it just looked cool.
In practice, it turned out to be more time consuming than I expected, and my results didn’t turn out as pretty as some of the examples I saw, but it was still a great learning experience, and I ended up with a functional solution.
Electrolytic acid etching sounds fairly technical, but it’s just a matter of combining a DC power source, an acid medium to support the chemical process, and an applicator. In this case, the medium is a blend of vinegar and table salt, and the applicator is a cotton swab. The swab is attached to the negative lead of your power source and dipped into the vinegar solution. The positive lead is attached to the kettle, so touching the applicator to the metal completes a circuit and the electric current pulls metal ions from the steel. The resulting surface is roughened and reflects light differently from the smooth, unetched metal.
This process should work for both stainless steel and aluminum, but from what I’ve read, a significant number of people have had problems getting a lasting visible mark on aluminum. It’s a good idea to try it out on the bottom of your kettle first to make sure that it will work as expected.
For simplicity’s sake, the instructions below refer to gallons. However, if you use another unit of measure, you will want to tailor the units of measurement to your preference.
- DC power source (Some people have used a 9-volt battery, and others have tried similar sized DC adapters. I used a 12-volt car battery charger, which already had clips attached.)
- ¼ cup (59 ml) white vinegar, with 1 Tbs salt dissolved in it
- A supply of cotton swabs
- Stencil materials (I used a combination of electrical tape and reusable vinyl stencils for the numbers.)
- Large measuring cup or gallon jug
- Latex gloves
- Alcohol wipes
- X-Acto knife
- Bar Keepers Friend cleaner
There are three steps: stenciling out the volume marks and associated numbers, the etching process itself, and clean up.
Create the Stencil
You’ll need to locate where the volume marks belong and mark them out. One approach would be to use a grease pencil to make the marks, and then create the stencil once you’re done. I chose to use electrical tape that I could cut at the appropriate points. Here are the steps I followed:
Start with a clean, dry kettle. Clean the area you will be etching with alcohol wipes.
Apply two parallel strips of electrical tape about 1/4″ (6 mm) apart to the inside of the kettle—they will be placed vertically, as shown in the photo below.
Place a few levels on the top of the kettle to make sure your water measurements will be precise (below).
Add a measured gallon (or your unit of preference) of water and wait for the surface to settle.
Cut the right-sided strip of electrical tape at the level of the water.
Repeat the preceding two steps until you’ve made the full range of marks.
Empty and dry the kettle.
For each cut on the right-sided strip of electrical tape, make a second cut a little higher, and continue to work up the side of the pot.
Peel off the resulting thin bit of tape between the cuts. At this point, the stencil will reveal a design that looks something like one-half of a ladder.
Apply reusable number stencils immediately to the side of each ladder rung, as shown below.
Before you continue, I think it’s important to keep in mind that you should take your time doing the etching. The longer you work each area of the stencil, the clearer the image will be.
Attach the negative lead to a cotton swab. If your lead is a loose wire, wrap it into the cotton puff, but leave the end of the swab clear. If you have an alligator clip, attach it to the cotton, below the top of the puff. You can see how I rigged mine in the photo below.
Attach the positive lead to the kettle, relatively close the specific area that’s being etched (you can see how I worked in the photo below). A loose wire can be taped in place. If you have a clip, it can be attached to the edge of the pot. You can also just hold it in contact with the metal if you prefer.
Dip the applicator into the vinegar solution.
Put the applicator in contact with the metal inside the bounds of the stencil. You should see some bubbling, and the liquid around the swab will turn yellow/brown.
Touch the applicator to each section of the stencil, making sure it is in contact with the kettle for at least 30−60 seconds in each spot. Redip the swab often to keep it damp.
Replace the cotton swabs when they become worn down and badly discolored and reattach the negative lead each time.
Wipe away excess liquid as necessary.
Once the etching is done, remove the stencil completely, clean the inside of the kettle using Bar Keepers Friend, and rinse the inside of the kettle.
In the process of doing this, I learned a couple of things. The first is that reusable number stencils can be tricky. Interior elements of the stencil sometimes slipped, making the number less distinct. Also, I needed to be more patient during the etching process. I ended up with some areas that were lighter than I wanted. Still, my first attempt was successful, and I’m looking forward to my next brewing session to try out my kettle.