Electronic cigarettes convert a specially formulated liquid into a vapor which the person inhales in a manner that mimics the way one inhales from a traditional cigarette. The liquid (which is sometimes called “juice”, “smoke-juice” or similar names) typically includes kosher-sensitive ingredients such as glycerin and flavors, and since the person imbibes the liquid/vapor, Rav Schwartz said that the liquid must be certified as kosher. We contacted a number of manufacturers who claim to use only kosher raw materials but there is no independent agency who certifies that claim, and therefore we are unable to recommend those products. [As with all medical issues, one should consult with their doctor before deciding to use or not use electronic cigarettes.]
Based on something I wrote in the previous post (Synopsis of YD §108), I disagree. For the record, I am simply elaborating on what I have already written here and here.
WHEN NON-KOSHER FOOD imparts flavor to kosher food, it renders the kosher food unkosher. Generally we assume that flavor can only be transferred through direct contact. What happens when there is no direct contact, but since the two items are roasting together in a small, sealed oven one can discern the scent of the non-kosher item on the kosher one while eating it? The truth is that ‘scent’ is the wrong word, because we aren’t referring to the something acquired via the sense of smell. This is a question of something which is discernible through taste, though it is of a subtler quality than flavor, and so we call it ‘scent’. Does this scent render the kosher item unkosher? This is known as the question/sugya of reicha (lit. scent). In Pesachim there is a disagreement about this particular case, and Rav says that the kosher item is now unkosher (provided that it meets certain specifications); while Levi says reicha lav milsa hi; scent is nothing [significant], i.e. the kosher item remains kosher.
A presumably related discussion about reicha occurs in Avodah Zarah about something known as a bas tiha. This is basically a straw-like contraption which one would use to inhale the vapor of wine in order to determine whether the wine was good. The question there is whether one may use the bas tiha on non-kosher wine, and Abbaye says it is forbidden because reicha milsa hi; scent is something, while Rava says it is permitted because reicha lav milsa hi; scent is nothing.
According to Rashi these two discussions are one and the same, and since there is a general rule that the Halacha follows Rava over Abbaye, the Halacha in the Gemara in Pesachim follows Levi, who like Rava in Avodah Zarah holds reicha lav milsa hi. The Rif accords with this view, as do most Rishonim, and they rule this way lechatchila. Accordingly, a non-kosher cigarette would be logically no different than the bas tiha, and it would be permitted.
Tosafos, however, make the case that the two discussions are not related. Without getting involved in the technical aspects, the following is a summary of their relevant conclusions:
· The discussion in Avodah Zarah and the one in Pesachim are not related.
· The Halacha in Pesachim follows Rav, that reicha is an issue.
· Technically, inhaling vapor via the mouth is Halachically considered drinking.
· The Halacha in Avodah Zarah follows the opinion of Rava, which is based on a unique consideration of the case of bas tiha which does not apply in most other cases. Bas Tiha, according to Tosafos, is not a Kashrus concern, because there is a physical discomfiture which occurs when one inhales the vapor with it.
Based on Tosafos, smoking a non-kosher electronic cigarette would presumably be Halachically considered ‘drinking’ it, and it would be prohibited since the heter of bas tiha is not present.
What is the final Halacha? The Shulchan Aruch rules in accordance with Rashi and the Rif. The Rema agrees according to the letter of the law, but holds that one should be concerned about the view of Tosafos barring cases of [great] financial loss. It thus appears at first glance that our question is the subject of a disagreement between the Mechaber and the Rema, and that those of us who generally follow the rulings of the Rema would be advised not to smoke such cigarettes.
However, it is not so simple. I believe there is good reason to say that there is no prohibition of reicha here simply because what is being smoked is not fit for consumption whatsoever (and therefore cannot retain a status of non-kosher). True, there is good reason to be stringent with reicha according to Tosafos, but all of the cases we see are ones where the item that is emitting the scent is fit for consumption and therefore not kosher. It thus makes sense to be concerned with secondary forms of flavor. But here, lo yehei koach haben yafeh min ha-av; let the power of the son not be greater than that of the father! – i.e. the scent cannot be non-kosher if the actual thing it is coming from does not have a non-kosher status. I believe that this is a valid avenue of reasoning. Furthermore, even the CRC only claims that it is questionable whether all of the ingredients in the flavoring are kosher. At the end of the day it is a safek, and those ingredients are anyway mixed into a mixture whose majority is certainly kosher. In this case it would surely be appropriate to rely on the Rif and Rashi, noting that even the Rema agrees that their opinion is the letter of the law and Tosafos is only a chumra. And I am not even getting into the fact that glycerin and various other additives are kosher anyway based on the responsa of R. Chaim Ozer Grodzinski, contrary to the position of the CRC and most other Kashrus organizations.
In conclusion, I believe there is a solid basis to unequivocally permit these cigarettes from a Kashrus perspective. However, there is no question that the final sentence of the CRC’s statement still stands: “As with all medical issues, one should consult with their doctor before deciding to use or not use electronic cigarettes.”
 Pesachim 76b s.v. Amar Lecha Rav
 Avodah Zarah ibid. s.v. Abbaye
 It should be noted that smoke is not necessarily the same as vapor. In fact it probably is not. The same Gemara in Avodah Zarah that we’ve been dealing with quotes a Baraisa which explicitly permits an Israelite to partake in something cooked in an oven that was fueled with cumin of Terumah. This is obviously a challenge to Abbaye’s opinion that reicha milsa hi. In Abbaye’s defense the Gemara says that this case is different, because mikla kali isureih; the prohibited item is burnt. The Shach (ibid. 12) brings this lehalacha. One way to explain the Gemara is that it is distinguishing between smoke and vapor, only the latter of which is ever included in reicha milsa hi in which case smoking non-kosher cigarettes would be permitted. I did not include this in the actual post because this would probably not be relevant to electronic cigarettes which, to my knowledge, work with vapor and not smoke.
 I also wish to note that the Aruch HaShulchan (108:25) explicitly permits smoking something which non-kosher wine was mixed to, though to be fair the non-kosher wine he refers to is only rabbinically prohibited.