How?
When the dough is prepared, cover it with a clean cloth and say the following blessing:
Ba-ruch A-tah A-do-noi Elo-hai-nu Me-lech Ha-o-lam A-sher Kid-sha-nu B'mitz-vo-tav V'tzi-va-nu l'haf-rish Chal-lah.
Blessed are You, L-rd our G-d, King of the Universe, Who has sanctified us with His commandments and commanded us to separate challah.
Then remove a small piece of dough (approximately one ounce); the custom is to burn the piece separately (e.g. in a piece of aluminum foil). It should be burned in the oven (preferably, in the broiler).
Why?
"Separate the first portion of your kneading as a dough offering. . .In future generations, give the first of your kneading as an elevated gift to G-d." (Numbers 15:30-21)
When the Jewish people first inhabited the Land of Israel, one of the many gifts they were commanded to give to the priestly tribe, (Kohanim) who served in the Beit Hamikdash, was a portion of their dough -- "the first and the best." This gift of food is known as challah, from which the name of our Shabbat loaves is derived. Since the destruction of the Holy Temple, the Bet Hamikdash, we may not give this dough to the Kohanim of today. However, in remembrance of this gift and in anticipation of the future Redemption and the rebuilding of the third Beit Hamikdash, we still observe the mitzvah of separating the challah portion.
When?
In regard to separating challah, there are three possibilities.
- Separate challah with a blessing;
- Separate challah without a blessing;
- Not required to separate challah at all.
Whether challah is to be separated or not depends upon the type of and amount of flour, and liquid contents of the dough.
Type Of Flour:
Challah is separated when the dough is made of one of, or a combination of, the following five grains: wheat, rye, barley, oat and spelt. Other types of flour such as rice, soy, corn, and buckwheat, when used without "the five grains," do not require the separation of challah. If they are used in combination with flour from one of the five grains, consult an Orthodox Rabbi as to the requirements for hafrashat challah.
Liquid Contents:
To separate challah with a blessing, the majority of the liquid contents of the dough should be water, provided that the flour requirements are met. If the majority of the liquid content is comprised of liquids otherthan water (such as oil, eggs, honey, etc.), challah is separated without a blessing.
In order to take challah, even without a blessing, at least some water should be mixed into the dough before the flour and liquid are well mixed together. If the recipe does not call for water, it is halachically advisable to add a drop of water.
Amount of Flour:
A. Do not separate challah when using flour weighing less than: 1230 grams or 2 lbs. 11 oz.
B. Separate challah without a blessing for flour weighing: between 1230 and 1666.6 grams or between 2 lbs. 11 oz. and 3 Ibs. 11 oz.
C. Separate challah with a blessing when using more than the following amounts of flour: 1666.6 grams or 3 Ibs. 11 oz.