Agreed, but im trying to brew professionally eventually, and since everything adds to the cost of the beer, learning to use the correct chemicals(lactic acid adds taste to beer in large quantities, phosphoric doesnt) in the correct amounts and sourcing larger quantities for cheaper becomes paramount.
I know a few breweries that use lactic to acidify their water without harm.
Didn't Kai's experiments show that it takes about 5ml in 5 gallons to notice the flavor? You are using close to that at 20ml for a 1bbl. Most I have used is about 2ml in 5 gallons.
I understand pinching pennies. Looking at your last grain bill (Kolsch from the Software Eff Thread), you must of had $60 invested in malt alone for that beer. $0.50 is less than 1%. At least 10% of my costs go to water with an additional 15% to propane. I'm not sweating a $0.05-0.10 for lactic acid.
Edit - not looking to troll. Just saying, don't sweat the small stuff.