Tasting the Shabbos foods on Erev Shabbos:
A. The law:
One is to taste the Shabbos foods on Erev Shabbos.
Which foods: It is proper to taste each and every dish of food.
B. The reasons behind the custom:
- Check if needs spices or other additions: The simple reason for tasting the Shabbos foods on Erev Shabbos is in order to see if they need anything added to them, such as salt or other spices, in order to ensure that the food will be tasty and appetizing when he eats it on Shabbos. This is similar to a servant who is preparing a meal for the king and tastes the food in order to make sure that it is good and if it is lacking any spices and if any other foods need to be made.
- Check if food is burning in order to abstain from getting angry with one’s family members: Some write that the reason for tasting the Shabbos foods on Erev Shabbos is to make sure the food is not burning in order so one does not become angry with his family members on Shabbos over the burnt food. On this the verse says “Veyadata Ki Shalom Ohalecha,” which means that one should make sure that there is peace in his tent. Now, if the Talmud learns based on this that one should make sure that the candles are lit on Erev Shabbos, then certainly one is to also verify the state of the food.
- Toameha Chaim Zachu: We are accustomed to taste the Shabbos foods on Erev Shabbos in order to fulfill the verse found in the Musaf liturgy “Toameha Chaim Zachu” which means that those who taste merit life. This itself is done out of honor of Shabbos. Those who are careful in this are rewarded with long days and years. Those who do so also merit to receive from the supernal life above.
C. Chabad custom:
Although the above custom is practically followed by some individuals, this was not seen to be the custom of the Previous Rebbe [seemingly relying on the tasting of other family members as brought in the Q&A.]
Must every member of the family taste the food or does it suffice for one person to taste it?
From most sources and reasons, it is implied that it suffices if a single family member tastes the food and it is not necessary for every family member to do so. However from other sources and reasons, it is implied that everyone should taste the food. Practically, many are accustomed to rely on the women tasting the food and do not personally taste it themselves, although some are particular based on mysticism to nonetheless taste at least one food.
May one taste the food if Erev Shabbos is a fast day?
It is forbidden for Ashkenazim to taste food on a fast day for the sake of benefiting from it, even if he plans to spit it out afterwards. However, it is permitted for Sephardim to taste food on a fast day without a blessing if he plans to spit it out afterwards. [However those were meticulous to fast every Erev Shabbos in order so they eat the Shabbos meals with an appetite, may taste the food and spit it out even if they are Ashkenazim.]
May one taste a meat dish on Erev Shabbos during the nine days?
One may taste a meat dish on Erev Shabbos to see if it requires any extra spices. [One is to simply taste the food and spit it out. One is not to say a blessing upon tasting it.] It is forbidden to eat it in order to fulfill the custom of eating the Shabbos food before Shabbos.
D. Saying a blessing over the tasting:
A blessing must be recited prior to eating and swallowing any amount of a food even if he is eating it for tasting purposes, to see if it needs spices. If, however, one plans to spit out the food, a blessing is not recited unless he chews/tastes a Kezayis/Revius or more of the food.
 Admur 250:8; M”A 250:1; Beis Yosef 286; Machzor Vitri 191 in name of Yerushalmi [unknown source in Yerushalmi]; Tanya Rabasi 17; Shibulei Haleket 82; Orchos Chaim Seder Tefilas Musaf 1; Kol Bo 37; Sefer Hamachkim p. 23; Mateh Moshe 408 in name of Yerushalmi; Shelah Miseches Shabbos p. 132 in name of Yerushalmi; Shiyurei Kneses Hagedola 250:2; Arizal in Shaar Hakavanos p. 62; Peri Eitz Chaim 18:3; Levush 286; Elya Raba 250:6; Olas Shabbos 251; Tosefes Shabbos 250:1; P”M 250 A”A 1; Chesed Lealafim 250:4; M”B 250:2; Kaf Hachaim 250:8; Likkutei Sichos 2:475; 20:173; Halacha Berura 250:11
 Admur ibid; M”A 250:1 in name of Arizal Peri Eitz Chaim 18:3; Shulchan Shlomo 250:1; M”B 250:2
 Mateh Moshe 408; Orchos Chaim Seder Tefilas Musaf 1; Kol Bo 37; Arizal in Shaar Hakavanos p. 62; Elya Raba 250:6; P”M 250 A”A 1; Chesed Lealafim 250:4; M”B 250:2; Shaar Hatziyon 250:8; Kaf Hachaim 250:8
Other opinions: Some Poskim negate this reason, as once the food is cooked there’s nothing left for one to do and adding spices won’t help, and therefore we must conclude that there is an intrinsic mitzvah involved in this tasting. [Mahariy Ayash in Bnei Yehuda p. 67; See also Shulchan Shlomo ibid, brought in M”B 250:2;]
 Arizal in Shaar Hakavanos p. 62
 Machzor Vitri 191 in name of Yerushalmi
 Shabbos 34a
 Beis Yosef 286 in name of Yerushalmi; Shibulei Haleket 82; Mateh Moshe 408 in name of Yerushalmi; Orchos Chaim Seder Tefilas Musaf 1; Olas Shabbos 251; Arizal in Shaar Hakavanos p. 62 [there he connects this reason with the previous reason of checking if it need spices]; Chavos Yair 160; Kaf Hachaim 250:8
Other opinions: Some Poskim negate supporting the custom of tasting food on Erev Shabbos based on the above verse stating that there is no source for saying so. [Meorei Or Kein Tahor p. 144]
 Machzor Vitri 191
 Arizal in Shaar Hakavanos p. 62 and Peri Eitz Chaim 18:3
 Likkutei Sichos 2:475; Shaareiy Halacha Uminhag 1:130; Shulchan Menachem 2:23
 See Halach Berurah 250 Birur 12
 The purpose of Minhag recorded in the Rishonim is to see if the food is tasty or needs any extra spices. For this purpose, it suffices if a single family member tastes the food. [Halacha Berura ibid]
 The Arizal and other Poskim says that one should taste each and every dish of food, irrelevant of the issue of taste, in order to merit the verse “Toameha Chaim Zachu.” Seemingly, according to this reason everyone should taste the food. Vetzaruch Iyun! See also the following Poskim will imply that the tasting itself contains an intrinsic Mitzvah irrelevant of whether it requires spices. [Shulchan Shlomo ibid, brought in M”B 250:2; Mahariy Ayash in Bnei Yehuda p. 67]
 Nimukei Orach Chaim 250; Likkutei Maharich
 See Halacha Berura 250:11 Birur Halacha 14
 Rama 567:1; Admur 612:7
 Michaber 567:1
 See Michaber 249:3 [omitted from Admur, and regulated in Admur 249:12 to only be permitted for an Istinis!]
 P”M 250 A”A 1; See However Toras Chaim Sofer 250 who negates this ruling
 Leket Yosher p. 210 brings a dispute in this matter; Makor Chaim 551:9; Hisorerus Teshuvah 2:169; Eiyn Eliezer 48; Rivivos Efraim 1:367; Shaar Shimon Echad 1:91; Piskeiy Teshuvos 551:40; See Chazon Ovadia Shabbos 1:22 [permits even swallowing]; Halacha Berurah ibid Birur Halacha 15
 Hisorerus Teshuvah ibid; See Poskim ibid
 See Admur 167:9; 168:7, Seder 8:10-11, Luach 2:11; 8:12; Michaber 210:2; Gemara Brachos 14a
 Admur in 168:7, Seder 8:10, Luach 2:11 that any amount of eating requires a blessing; Admur 167:9, Seder 8:11, Luach 8:12 that “Benefit is considered the benefit of one’s stomach [i.e. swallowing] and only if he spits out the food he tastes is a blessing not recited”; second opinion in Michaber 210:2; Tosafus Brachos 14a in name of Rabbeinu Chananel in interpretation of Braisa “Tasting does not need a blessing”; Rosh 2:6 [see Beis Yosef]; M”A 211:7 and 10 that this is the main opinion; The following Poskim explicitly rule this way regarding Erev Shabbos tasting: Chavos Yair 160; Yad Aaron on Tur 210; Mahariy Ayash in Bnei Yehuda p. 67; Kaf Hachaim 210:23; Chazon Ovadia Shabbos 1:23; See Halacha Berura ibid Birur Halacha 13 that tasting the food on Erev Shabbos a blessing set according to all being that one has intent to actually eat the food and benefit from it in order to fulfill the mitzvah and it is proper to have this explicitly in mind when eating it
The reason: As it is forbidden to benefit from this world any amount without saying a blessing. [Admur 168:7, Seder and Luach ibid]
Other opinions: Some Poskim rule a blessing is never recited upon tasting less than a Revius of a food, even if one swallows it. If, however one tastes a Revius of the food, a blessing is recited [See coming footnotes for dispute if this applies even if he does not swallow it]. [1st opinion in Michaber ibid; Tur 210 in his Stam/main opinion; Implication of Rif and Rambam Brachos 1 in interpretation of Braisa Brachos 14a “Tasting does not need a blessing, up until a Revius”; Beis Yosef 210 that we follow Rif/Rambam as well as Safek Brachos Lihakel; Rama ibid concludes that Safek Brachos Lihakel. This means that a blessing is not to be recited upon tasting a food unless one a) swallows the food as requires second opinion and b) eats a Revius as requires the first opinion. [Ateres Zekeinim 210 in explanation of Rama ibid; M”B 210:35] Many Poskim conclude like the Rama ibid. [Beis Yosef 210; Elya Raba 210:5; Mamar Mordechai 210:14; M”B ibid; Kaf Hachaim 210:31] and hence when swallowing less than a Revius one is to intent to do so for eating purposes in order to say a blessing [M”B ibid in name of Chayeh Adam; Kaf Hachaim 210:22; Piskeiy Teshuvos 210:9] or is to think of the blessing in his heart. [Kaf Hachaim 210:22]
If one tastes the food for purposes of eating: If one tastes and swallows the food for the purpose of eating and not for tasting purposes, a blessing must be recited according to all opinion even if the amount is less than a Revius. [M”A 210:6 as brought in Michaber 210:1] It is however disputed as to the definition of tasting for the purpose of eating. According to Rashi Brachos 14a this means that any taste which is not for the sake of adding spices, such as simply to see if the food is tasty, requires a blessing. However, according to the Rokeiach 209, even in such a case a blessing is not required so long as he desires to eat more and stops himself, and only an eating which one does not desire to eat more requires a blessing by less than a Revius. [M”A ibid; see Machatzis Hashekel] Practically, we rule like the Rokeiach ibid that tasting to see the taste is still considered tasting. [M”B 210:13 in name of Elya Raba and P”M]
 Seder 8:11; Luach 2:12; This follows both the 1st opinion in Michaber ibid that only tasting a Revius or more requires a blessing and follows the 2nd opinion in Michaber 210:2 that spitting out never requires a blessing. [Thus, everyone agrees that tasting less than a Revius which one will not swallow does not receive a blessing.]
The reason: As benefit is considered the benefit of one’s stomach [i.e. swallowing] and not just the benefit of one’s mouth. [Seder and Luach ibid; See also regarding not making a Hefsek between eating and swallowing: Admur 167:9; Seder 9:1; Luach 6:1; M”A 167:16; Shelah Shaar Haosiyos Kuf; Ketzos Hashulchan 37:7]