While brewing my first batch of beer from a 1-gallon all-grain kit, I realized pretty quickly that the 6 quart stockpot I had in my kitchen wasn't quite going to cut it.
If I was going to keep brewing I needed to invest in a kettle that was the right size, and if I was going to invest in a dedicated brew kettle I should customize it for brewing. One of the main features I wanted to add was dedicated volume markers on the side, so I knew exactly how much wort evaporated during the boil.
By the end of this instructable you will have selected a brew kettle and electrochemically etched volume lines into its inner wall.
Step 1: Select a (Stainless) Brew Kettle
First, you need a kettle - and when choosing a kettle, your main concern needs to be size. Your kettle needs to be large enough to hold not only the full volume of the wort that will become your beer, but additional water to cover things like evaporation, kettle deadspace (the water left after you transfer to your fermentation vessel), etc. Below are the kettle sizes I recommend based on the amount of liquid you want to transfer to your fermenter.
Recommended Kettle Size:
1 gallon batch: 2 gallon (8 quart)
2.5 gallons batch: 5-8 Gallons
5 gallon batch: 8-10 Gallons
10 gallon batch: 15-20 Gallons
Other than size, you will need to think about what features you would like. Features such as welded ports, integrated thermometers, silicone-covered handles, and the like can all be handy - decide what fits your budget and your brewing style.
For my first brew kettle for one gallon batches, I chose a stockpot similar to this one - Inexpensive, but (importantly) made of stainless steel.
Step 2: Acquire Materials
With your kettle acquired, it's now time to obtain the things you'll need to etch it. You will need the following:
Quart or Gallon Pitcher
Glass pyrex cup (or other microwave-safe vessel for heating liquid)
Remember - You will be etching areas of exposed metal, so you will need stencils that cover the area you do not want etched.
Step 3: Measure Your Kettle
Determine what volume you want for your kettle's markings. I recommend quarts for 2-3 gallon brew kettles, and either half gallons or gallons for larger kettles.
Once you've determined where you want your markings, it's time to start measuring! Add one quart of water to your pitcher (or half-gallon, or gallon if that is what you want the markings in your kettle to denote) and add it to the kettle. Using a pencil or a marker, mark the top of the water line. Refill the pitcher and repeat this process until you have measured & marked the entire kettle.
Step 4: Mask Your Kettle
Once you know where on your kettle you need to etch volume markings, it's time to mask the markings themselves. Using masking tape, outline a small line or box where you want the volume markings to be. Don't worry about using too much tape - be sure to cover around where you don't want etched.
Remember - you are etching where the tape isn't. The exposed metal is what will become your line.
Step 5: Prepare Your Etching Tool
You're now almost ready to begin etching - but first you need to prepare your etching tool. In a small bowl, mix vinegar and salt (The amount of salt doesn't matter - you are using it to allow electricity to flow through the vinegar) and then soak the tip of the q-tip in the salt-vinegar solution. Next, wrap the black (negative) wire around the tip of the Q-tip. This is your new etching tool!
Step 6: Etch Your Volume Lines
While pressing the red (positive) lead of the 9V battery clip firmly against the metal wall of the kettle, touch the etching "tool" you just created to the bare metal in between the masking tape lines you created earlier. Remember - everywhere you touch the "tool" will be etched, so be careful! Periodically dip the end of the etching tool back in your salt-vinegar solution to rewet.
As you do this, you should see bubbles coming from the tip of the tool and the end of your tool will gradually darken. Small amounts of metal are actually being transferred from the wall of your kettle to the tip of your cotton swab. Neat, huh?
Step 7: Unmask, Remask, and Add Stencils
You've now successfully etched your volume markings! Let's remove the mask, and take a look. Peel off the masking tape, and you should see etched lines where you used your etching tool.
Before we finish etching the kettle, apply adhesive stencils where you would like numeric markings. This can be every volume line, every other volume line, every third - the choice is yours! To align the stencils it can help to use a line of masking tape along the edge of your etched volume markings.
As an optional, added bonus - add stencils/custom artwork. This is your brew kettle - make it how you want it!
Step 8: Etch Your Stencils
Once again, use your etching tool to etch your stencils.
Dip the end of your etching tool into the vinegar-salt solution. Press the red (positive) wire from the 9V battery clip against the wall of your kettle, and then press the end of your etching tool against the exposed metal showing through the stencil. You may see small bubbles of chlorine gas forming.
Move the etching tool slowly across the exposed metal on each of the stencils, being careful not to touch any areas of exposed metal you do not want to etch. Once you have successfully etched every stencil, wipe the stencils off with a damp paper towel, and remove the stencils.
Step 9: Passivate Your Etchings
Now that everything is etched, it's time to passivate your etchings.
Passivation restores the protective oxide layer to the surface of the stainless steel, preventing the metals in the stainless from leeching into your beer (and protecting it as well).
Heat your lemon juice in the microwave until it is hot, but will not burn you. Fold a paper towel several times, and then place the paper towel over your etchings. Pour the hot lemon juice over the folded paper towel, and leave for 30 seconds.
Step 10: Clean Up, and Enjoy!
All that's left at this point is to clean up! Throw away your lemon juice-covered paper towels, and rinse your pot with clean water. Wipe off with a paper towel, and admire your work!
Congratulations - you now have a custom-etched brew kettle!