Yitzchak's favorite food

Yitzchak asked Eisav to prepare his favorite food for him (27:6),  וַעֲשֵׂה לִי מַטְעַמִּים כַּאֲשֶׁר אָהַבְתִּי וְהָבִיאָה לִּי וְאֹכֵלָה.  R' Shteinman in Ayeles haShachar asks a question only someone like R' Shteinman could ask: Why would a tzadik have such a thing as a favorite food?  You have to be a tzadik yourself to be bothered by questions like this.

Later in the perek we are told that Rivka prepared the food Yitzchak liked in order for Yaakov to bring it to his father (27:14),  וַתַּעַשׂ אִמּוֹ מַטְעַמִּים כַּאֲשֶׁר אָהֵב אָבִיו  I don't understand why Yitzchak was fooled by this.  If I were blindfolded and served something my wife cooked alongside the same dish prepared by someone else, I am pretty sure I could tell the difference between the two.  After so many years of marriage, how could Yitzchak not be able to tell the difference between some wild game prepared by Eisav and the cooking done by Rivka his wife!?  Was his completely oblivious to the sense of taste?

I usually don't like practical questions like this, but I'll make an exception for myself in this case because I found a Sefas Emes (5631, and see last year's post as well :

ובחי' המטעמים הוא ג"כ לקרב עניני עוה"ז להש"י ומה שהוא יותר מרוחק יותר נייחא לעלות להש"י. [כי במקום הנסתר לא יש רק הטעם שבחי' טעמים הוא למעלה מהכל וממילא נמצא ג"כ במה שלמטה יותר והבן מאוד]. ולכך ביעקב שלמעלה מהטבע לא הי' לו זה רק ע"י שרימה את יצחק בהברכות ע"פ רוה"ק של רבקה הי' עלי' כמטעמים שצוה לעשו כנ"ל. [ וז"ש הקול כו' והידים כו' וזה עליות הגשמיות לבחי' הקול כנ"ל]:

What made Eisav's food into מַטְעַמִּים כַּאֲשֶׁר אָהַבְתִּי for his father is not the way he seasoned it or the way he cooked it.  Like R' Shteinman says, things like that could not have mattered to Yitzchak.  What made the food Yitzchak's favorite is the fact that Eisav went out into the field, went out into olam ha'zeh, and took something out for the sake of ruchniyus.  To be a "yosheiv ohalim," plugged into spirituality 24x7, and remain a frum Jew, is not such a big kuntz.  But to go out into the world, where you don't see the yad Hashem, and not just to remain pure, but to even elevate that world and bring something positive out of it, that's a big deal.  That's the avodah that Yitzchak thought Eisav was engaged in.  

That's why, says the Sefas Emes, in this case, Yaakov's food as prepared by Rivka had that same flavor.  However you explain the details of why and how, Yaakov here seems to deceive his father and use the tools of our world of sheker to advance his cause.  It was this flavor of elevating our world of sheker and hester, the same flavor that Eisav was supposed to deliver,  that Yitzchak detected and savored.  

 הַקֹּל קוֹל יַעֲקֹב וְהַיָּדַיִם יְדֵי עֵשָׂו.  Sometimes we need to use the tools of Eisav and not just be a "yosheiv ohalim."  We sometimes need to get our hands dirty and take care of things in olam ha'zeh and it maybe doesn't look so nice.  So long as those hands are an extension of קוֹל יַעֲקֹב and are guided by the voice of morality and justice, they are elevated to something holy.