Before Sushi

 Parshas Hashavua Toldos.

                                                   

This vegetable is served at Simchos. It is also
mentioned in this week's Parsha.

The מדרש writes that יעקב served lentils to עשיו
because it symbolizes אבילות & שמחה. The אבילות was
for Avraham's death The שמחה was for Yaakov's
acquiring the בכורה.
רש"י quotes the תנחומא that Lentils are served
at Simchos.
The עץ יוסף explains that perhaps they served lentils
at Simchos to remind them of the יום המיתה.
(similar to breaking a glass)

--------------------------------------------------------------------------------

There are numerous answers to why יעקב served
wine to יצחק when all he asked was for food.
             
The שר התורה Harav Hagaon Chaim Kanievski זצ"ל
had a simple answer.
" יצחק enjoyed eating venison. with a glass of wine".
  מטעמים כאשר אהב אביו