Could Yitzchok not taste the difference between game and goat meat?

Question

Do any meforshim discuss the fact that Yitzchok requested Esav to prepare him a dish of game meat, but Yaakov serves him goat meat? Why couldn't Yitzchok tell the difference between game and goat meat?

Answer 1

Rashi had the same question. See Bereshit 27:5, where he says "For the taste of a kid is similar to the taste of a deer."

Answer 2

Another relevant point to the answer of יהושע ק, may come from mishna Bekhoros 4:7:

הֶחָשׁוּד עַל הַבְּכוֹרוֹת, אֵין לוֹקְחִין מִמֶּנּוּ בְּשַׂר צְבָאִים וְלֹא עוֹרוֹת שֶׁאֵינָן עֲבוּדִין.

In the case of one who is suspect with regard to firstborn animals of slaughtering them and selling their meat when it is prohibited to do so, one may neither purchase meat from him, including even deer meat, nor may one purchase from him hides that are not tanned.

R' Ovadia m'Bartenura comments:

בשר צבאים – for it (i.e., deer/gazelle meat, venison) is red and he switches it with the meat of a calf, and sometimes, when he sells the firstling of a pure calf and he said that it is the meat of a deer/gazelle, where we aren’t troubled by a firstling.

I.e. venison, the meat of a deer, is light red like veal, while the goat meat is dark like beef, even when prepared. Because Yitzchak was blind he could not see the difference, he had to go by the smell and taste.

Also in Kiddushin 70a, a man offended Rav Yehuda bar Yechezkel as Yehuda bar Sheviske’el, which some translate eater of deer meat. The deer meat is similar to veal in appearance. I.e. a kohein is supposed to eat first born calves, but he got easier available deer meat instead.