I'm halfway through reading John Palmer's book "How to Brew". Decided to make my first yeast starter last night follow the starter wort recipe listed in his book, which is 1/2 cup DME to 2 cups of H20. I ended up getting a 1.090 gravity wort. I had to water it down and reboil, had a boil over and finally brought it down to 1.048. Many YouTubers and brewers in forums stand by this recipe. It's absolutely wrong. I learned from some fellow brewers that it should be 100 ml H20 per 1 gram of DME. Whats the deal?
UPDATE!
I was reading the 3rd edition. Palmer put out the 4th edition in 2017 and corrected this!