I left my last two lagers in the primary for 21 days before racking and lagering. Fermentation had definitely slowed after 6 days. I was going to let it sit for another week for a diacetyl rest. It ended up being two weeks because I got sick.
I let it lager for 3.5 weeks, so 48 days total. Could have been 41 days.
So, here's the question: does "brewed 21 days" mean fermented or fermented and lagered?
Fermented 21 days seems long. Fermented and lagered 21 days seems short but wouldn't surprise me for a tasteless and heavily filtered beer.
If I'm doing an ale, it's done fermenting in 7 - 10 days. I usually wait until the next weekend to bottle. So, it would be 14 days brewed.