>>aged too long
potentially not - but the dry aging did not happen under the right / recommended conditions. I suspect it was already tough and dry at 20 days; 35 days only made it tougher / drier.
the ambient humidity was too low; the proper temperature kept the bacterial growth in check but the meat lost too much moisture. that thing about "moist and juicy" . . .? got violated before it ever saw a grill / heat..
the recommended higher humidity prevents the cut from drying out too much; keeps the moisture content "in the range" when the enzymes can appropriately do their thing.
if one wants to dry age a chunk o'beef at home, here's some thoughts:
(sorry, this doesn't fit in the 128 character Tweet format the world of today uses)
first, you need to know what the history of the meat/cut is.
if one is unaware, pretty much anything in the supermarket that has been "cut/packaged" locally came to the supermarket meat department as a wet aged cryo-packed cut - primal or smaller. typically in the trade, "wet aged meat" is held 20-30 days prior to shipping to retail.
my butcher deals directly with a local slaughter house; he hangs the primals in his locker. he does no such thing as "wet aging"
so when I buy a couple Delmonico steaks at his shop, they've dry aged roughly 10 days already - my dry aging at home only needs 4-5 days to 'concentrate the flavor' - the enzyme "controlled rotting / tenderizing" has already started happening.
come holiday time and only on special / advance order - he cuts / dresses the specific size / number of ribs / large end / small end / whatever you order.... from a really fresh primal and holds it in his dry aging locker for up to 21 days. this is the melt in your mouth, no knife required kind of beef.
bottom line, whether from a mega-chain source or a local shop, odds are the beef has been aged - wet or dry - 10 to 30 days before you buy it. "for best results" you can dry age it in your fridge for another 5 days - up to ten days if you are more daring.
a home fridge is _not_ the ideal temp/humidity/bacterial conditions for doing extended dry aging - and as some body has in their tag line - fuzzy green meat is bad for you.
second, check the temperature of the home fridge. if you can't maintain less than 40'F - aging past 3-5 days is an iffy proposition from a bacterial count standpoint. somedays you'll get away with longer, somedays you won't.
third - the 'cut' plays a huge role.
a roast type chunk takes longer - especially if covered by a 'fat cap'
a couple steaks - with the large cut surface area - dry age much faster than a roast.
how much is enough / too much?
for pre-cut steaks I've found five days about optimum.
for roast cuts, 15 days.
and, you'll see dry aging touted as if it is only of value for USDA Choice "best cuts" - well, hoggy wash. a rather run of the mill steak/roast cut of any grade is seriously improved with a bit of "home style" dry aging.
for the "did I go too dry?" bewonderment, here's what I've found:
background: I rarely do marinades - much more a a dry rub house here.
apply the dry rub - which one assumes has a generous salt percentage - to the meat and allow to stand at room temp for one-two hours. if the salt does not bring water to the surface - which makes for a really mean sear, btw,,,, - it's been done too dry.