I have what many would consider an addiction to chocolate and I have chocolate every single day. The specific brand of chocolate that I eat all contain hazelnuts to some degree. In previous years from Rosh Hashanah until after Simchas Torah I would simply by the chocolate flavor that doesn’t have nuts in it, however, I recently discovered that all the flavors have hazelnuts in them even the ones which are technically not nut flavored, although they do have a lesser amount of nuts. Bottom line, is there an issue with me eating such chocolate during Rosh Hashanah? Is the issue of eating nuts only when one eats plain nuts or even when it is eaten within a food?
Practically, it is best to avoid eating all foods that contain nuts throughout Rosh Hashanah, including chocolates, cakes, and cookies that contain such nuts. This especially applies to hazelnuts or walnuts or any other botanical nut [i.e. Egoz]. Nonetheless, those who are lenient have upon whom to rely, and may choose to be lenient if they wish, as this is not forbidden from the letter of the law and is likewise not forbidden due to the custom of avoiding nuts. This allowance and leniency especially applies after Rosh Hashanah, in which many do not even have a custom to avoid eating nuts at all, and so was the accepted custom amongst some vintage Chabad Chassidim.
Explanation: There is no actual prohibition against eating nuts on Rosh Hashanah, and rather the Shulchan Aruch records it as a mere custom which is only followed by some individuals. Practically, in today’s times the widespread custom is to follow this stringent custom and avoid eating nuts on Rosh Hashanah. There are two reasons recorded for why some avoid eating nuts on Rosh Hashanah: 1) Due to that it increases saliva and phlegm, and causes one to nullify his prayers. 2) Due to that Egozim is the Gematria of sin and hence is avoided. Now, it is unclear according to either reason whether this avoidance would apply even if the nut is found in a mixture. Practically, some write [on a basis that I am not aware of] that in a mixture only the second reason applies as nuts do not increase in saliva and phlegm when eaten in a mixture. Accordingly they write that there is no need to avoid eating foods that contain nuts that are not defined as Egoz, which would include all non-botanical nuts such as peanuts, pecans, cashews, almonds and the like. Likewise, even if it contains the Egoz nut it is not an actual prohibition. Now, according to the above assertion, one may argue that according to the opinion of the Alter Rebbe who completely omits the second reason above for avoiding nuts due to it being numerical value of sin, that he holds that only the first reason applies, and hence one can eat all foods that contain any type of nut in them, including Egoz. Practically, since this entire matter is based on a custom, and the widespread custom today is to avoid all nuts, and to hold of both reasons for its avoidance, therefore I concluded above that it is best to avoid on Rosh Hashanah, even though one who desires to eat it may certainly choose to do so, and so conclude some of todays Poskim. However, after Rosh Hashanah certainly one may be lenient being that the main custom is only to Rosh Hashanah itself and not throughout the period until after Sukkos.
Sources: See regarding eating foods that contain nuts: Beir Moshe 3:97; Yad Yitzchak 1:208; Piskeiy Teshuvos 583:7; See regarding the general custom to avoiding eating nuts on Rosh Hashanah and its reasons: Admur 583:6; Rama 583:2 [“Some do not to eat Egozim as it is the Gematria of sin and causes saliva”]; Darkei Moshe 589:3 in name of Mahril; Other opinions: There were some Poskim that did not avoid eating nuts as well as other foods that increase seed. [Darkei Moshe 583:1 in name of Kol Bo; Kaf Hachaim 583:26] See regarding avoiding eating nuts even past Rosh Hashanah: Reb Nosson Adler as well as the Chasam Sofer were not particular against eating nuts after Rosh Hashanah. [See Beir Moshe 3:97; Piskeiy Teshuvos ibid footnote 38] There is no record in Chabad literature of the custom of avoiding sour foods past Rosh Hashanah. Likewise, Rav Eli Landa Shlita, Rosh Hayeshiva of Kefar Chabad, and late son of Rav Yaakov Landa OBM, related to us that in Chabad we only avoid eating sharp foods on Rosh Hashanah. Likewise, see Otzer Minhagei Chabad p. 148 that the Rebbe Rashab ate a very sour new fruit on the second night