Boil off in unmarked kettle

Get some brewing software (will take into account boil-off rate) and/or get a larger kettle or else you will likely be doing exactly that.

Other options are brew smaller batches or split your boil into 2 kettles.
Markings aren't really needed as long as you can use a handle rivet or something similar as a reference point, imho.

 

Put some markings on it yourself, that is what I did. Or simply trial and error. Start with the standard boil off rate and see how much goes into tje fermenter. If you over shoot volume then adjust. Keep doing that and you'll get a solid ballpark.

 

I have an unmarked kettle as well. I use a plastic yard stick to measure the depth of the liquid. And since I know the radius of my kettle, a little math gives the volume.
V=pi x r^2 x h
Then convert cubic inches to gallons with an online calculator.

Like all brewing tools, I wash and sanitize the yard stick.

Cheers

 

I cut little notches in my plastic stirring stick, and I figured out the notch locations the manual way: Add a gallon of water to the kettle, notch, add another gallon, notch, etc.

 

7 gallon pot is usually too small for 5.5 gallon batches. I used a seven gallon pot for a year, and with my boil off rate, I needed 6.75 gallons at the beginning of my boil. That left no room for boil over mitigation. My kettle was also unmarked, so one day I measured off 5.5 gallons of water, put it in the pot, and used my brew spoon as a depth gauge. I held the spoon against the side of the kettle to make it an easily duplicated measurement and notched the spoon. When I upgraded to 15 gal, I did the same thing with my spoon. It now has 5.5 gallon, 7 gallon, 11 gallon , and my lower handle rivet is 14.

 

This is roughly what I do. No need to sanitize the yard stick unless you are measuring when the wort has cooled down after the boil.

 

Some kind of notched or otherwise-grduated stick is the simplest way, as long as your pot has a relatively flat bottom. It's a little trickier if you boil in a keg w/ concave bottom since you always have to be careful to measure in the center where it's deepest.

FWIW, getting a kettle with a graduated sight glass was one of the greatest things I've done with regard to improving consistency and hitting my gravity and volume targets.

With enough experience, you can fudge your way through in other ways (as I did for many years measuring strike water with a 2- or 3 qt. kitchen pot), but it's so much simpler to measure strike water volumes, gauge the volume of runoff you've collected, make pre- or post-boil volume adjustments, etc. when you can look at the side of the kettle and know at a glance how much is there.

 

I believe the process is called electrolytic etching:

I did it myself. It was a pain in the ass and took a lot longer than I expected, but I'm glad to have the markings. I did gallons 4 through 7 on my 10 gallon kettle, although I kind of wish I had gone up to 8 instead. But I was so fed up with the process that I didn't want to bother with any more...

 

I've been thinking about doing this. What part took the longest?

 

It took me a long time to realize that the etching is just a fairly slow process, so I wasted a bunch of time at the beginning questioning how I was doing things. Maybe my setup wasn't ideal, but I found it took a fair amount of time to etch a simple line, all while fussing with the q-tip and trying to hold the wires in the right spot. You also want to start with a fresh battery. It's been about 2 years, so I've forgotten the details, I just remember being glad it was over (but also really happy to have the lines). I actually etched lines into my 5G kettle, too, which I never use anymore.

 

THIS.
I didn't have markings on my homemade electric keggle, and after almost 40 full years of using it, I still don't have markings on it but still almost always end up right on target volume-wise. To be clear, it didn't take 40 years to find the right levels...it was only a matter of brewing frequently and taking detailed notes of the whole process. The bonus of doing that was a very high level of repeatability an near perfect consistency when I wanted to recreate a favorite batch or recipe.

By trial and error (and taking good notes), you gain solid brewing experience AND you wind up with a good supply of homebrew,,,it's a win-win situation.
I eventually reached a point where I could simply "eyeball" the level and volume of boil-off.

 

I will experiment with stronger batteries.

 

Take all the notes you want. The fact remains that it's easier to take *better* notes with an accurate sight glass, and it takes a lot of guesswork (even the educated kind) out of the equation. True you can brew great beer with nothing but a healthy amount of trial and error, but a good chunk of 'error' can be avoided right off the bat with good volume measurements. For the record, I did it your way for a long time, too, and made great beer. But... I wouldn't want to go back.

 

A does not = B ...I usually agree with you, but I humbly disagree on this one. Things like hopping rate, use of whole cones, hop bagging, ambient temp/boil -off rate, and self-medications during the brew day are much bigger factors .

 

Lol. Fair enough. But hops etc don't factor in to the volumes of my strike water added to the mash tun, or the volume of water transferred to my HLT for the sparge, or the pre-boil volume in my kettle. And, if I get all of those things right? The post-boil volume *usually* takes care of itself. And, on those occasions when it doesn't (cold, low RH days, mostly, when boil-off is higher), it's easy to adjust w/ just a gravity measurement and a *reasonably accurate* measure of post-boil volume.

 

I usually only worry about final volume of the batch into the fermenter. Mash and boil volumes can be easily ciphered/estimated if you've ever had oatmeal and like hopbombs...what I mean is, if you strive to get your mash the consistency of at least oatmeal and your sparge/boil volume to take into account the amount of whole cones (bagged or unbagged) you are using...the rest usually takes care of itself. It's when I'm brewing different styles with less hops and different encapsulation methods (and maybe different burner) that I have to adjust from my usual rule of thumb: 7.5-7.75 gal of total water for a 5 gal batch...but hey, that's my method on my equipment