Cite? That's a very strong claim & one contrary to my experience.
This is more of a common knowledge thing. If you are making the same IPA or RIS sure it will taste good but the same? Prob not and here is just a few reasons why!
Hops: Hop quality varies from farm to farm and year to year. The stuff in a homebrewers small oz-lbs bag can be a grade A to grade C hops and I am guessing you do not test each pack opened. Do you track the age of the hops and storage conditions to determine degradation? (Most homebrew hop packs lack the required info...) Do you purge the O2 out and reseal the hops you do not use or discard them?
Grains: Like hops they alter from farm to farm and year to year. Do you track the lot numbers and shake test your crush? Do you measure your mash temps down to .1F or closer? What about mash thickness?
Water: Do you start with DO or RI water and measure salts/acids accurately enough to determine the ppm to .1? What about ACCURATELY monitoring PH levels during mash, lauter, boil and fermentation to .1 or closer?
Yeast: Do you do a cell count on the yeast you are going to pitch and then afterwards to ensure the correct number is in the wort? What about testing/knowing the O2 levels in the wort previous to pitching? Yeast growth/activity is also influenced by moon phases.
If you answered No to the bulk of the above questions your beer does not taste the same. All of things can and will alter the flavor of the finished beer, your palate may not be able to detect it but other peoples can. At work we keep RIDICULOUS records, including weather conditions and tasting notes and we have issues with repeatability. Knowing this I can easily say that 99.9% of homebrewers, that have less equipment/less accurate equipment and keep less records can not do it.
Once again this is
not saying homebrewers are getting close or making bad tasting beer but to claim to be on par with commercial breweries is flat out outlandish when talking about repeatability.
/end thread jack