I started out brewing in January of this year and did my first few brews in my kitchen. They were partial volume boils. Three gallons in the pot and a top off to bring to 5 gallons. Then I bought an 8 gallon megapot and a darkstar burner. I now brew outside. I recently did a brew that was the same kit as one I did as a partial boil batch and the flavor is different and in a negative way. Not sure what the problem is. One thing I am considering is that I am able to get a rip roaring boil with the darkstar while on my stove I had more of a subtle rolling boil going. Is an aggressive boil a good thing or a bad thing? SHould I be shooting for a slow rolling boil or a rip roaring boil? I did not see any evidence of burning. And the flavor is not that of burnt. It’s more of a sour flavor. All my gear is very well cleaned and sanitized so I am ruling out contamination.
A rolling boil helps eliminate the pre-cursors to DMS. Your off-flavor has to be contributed to something else cause rolling boil definitely wouldn’t cause a sour flavor.
You say that you now brew outside. Could the wind have maybe carried something into your fermenter when you were draining the kettle? Wild yeast strains will cause a souring.
Keep it down t a gentle boil. Only part of the wort surface needs to be rolling to have boil temperatures. Rip-roaring will only increase the boil off volume and darken the wort
Sour would not be a taste caused by to vigorous of a boil. Our palettes are different though. Perhaps what you perceive as sour is increased bittering from isomerization of hop oils.
I do my boil outside but I cover after the boil while the wort is still hot enough to kill off natural yeasts. I drain the kettle inside in a rather clean and still environment. I suppose the issue could be better isomerization of hop oils. If so then I either have to “mature” my pallette, or figure out how to reduce that.
If your doing a full boil use the hop addition from the all grain kit it will be less than the extract kit.