I guess graduated pots can't be trusted

I like playing the over/under

 

https://en.wikipedia.org/wiki/Over–under

Think of your OG as an over/under bet...if you hit it exactly great! ...but it's more of an estimate and you will either be over or under...with experience, you can tell a high % of the time where it's going to land (without really measuring exactly) ...Nevada humor I suppose Cheers

 

I'd send them an email and see if they're willing to do anything about a faulty product. Time to pour a gallon and mark the yard stick. Pour another gallon and mark the yard stick etc. etc..

And you say you've measured the your new mash tun? For sure for sure?

 

What are you using to accurately measure the pot? I've found that some measuring cups are also not too accurate, so when measuring a large quantity, the lack of accuracy magnifies.

 

Good way to check volume is by weight. Remember, 8.34lb water per gallon! Just make sure your scale is accurate, too...

I do all my mash and sparge volumes by weight.

 

Don't forget, that's at 39 F. At boiling point, for example, 1 gallon of water weighs 8.0 lb.

 

With all of my containers I use separate hardwood dowels to measure the amount of water or wort. Each of these dowels was made before-hand by marking the volumes (for example each half gallon or gallon) on the dowels with a permanent ink marker. I find these very handy and use them all the time. For the brewing vessel, I use one for measuring the total volume of wort, the amount after boiling, and later the amount of trub I have left over. All these measurements help in calculating proper volumes in subsequent batches.

 

Tasty.

 

I have the mega pot 8g and my markings are off as well. Once you know you can adjust, but have never contacted them to see what's up.

 

I have several pots. Only the last one I got was graduated, but I made a dipstick for that one anyways, since I had done it for the others. I don't remember exactly what it is - it's not from a dedicated homebrew place, but the markings were pretty close - give or take a cup or so either way. I generally don't worry too much about exact measurements anyway when brewing - pretty close is good enough for me - if I mess up my count and use one quart too many or too few with mashing, it's not going to affect my brew enough to worry about. As long as I end up with about 6.5 into the kettle, I'm good. I know what I expect for an OG, but if I'm .005 off, I don't stress about it.