Halakhah for Nazir 68:6

He prohibited the nazirite from eating grape skins. And that is His saying, "to the skins, etc." (Numbers 6:4). And if he ate a kazayit of them, he is lashed. And the proof about each one of these five types - meaning to say, wine, grapes, raisins, seeds and peels - being a separate commandment is that one is lashed [a separate set] of lashes for each one of them. And the language of the Mishnah (Nazir 34b) is, "And he is obligated for wine on its own, and for grapes on its own, and for grape seeds on its own, and for grape skins on its own." And in the explanation, they said in the Gemara, Nazir (Nazir 38b), "[If] he ate fresh grapes, raisins, grape seeds and grape skins, and squeezed a cluster of grapes and drank [the juice], he is lashed five [times]." But when they counted, so as to uphold the words of the teacher - such that [it turns out that] he taught and left [something] out, so that one would be obligated more than five [sets of] lashes - they said, "But behold, he left over the negative commandment of, 'he shall not desecrate [his word]' (Numbers 30:3)!" But they did not say, "But behold, he left over vinegar! For he is not liable twice for wine and vinegar. As vinegar is actually forbidden because the source of its prohibition (wine) did not recede with its decay. And what is appropriate for you to know is that all of these prohibitions of the nazirite combine for a kazayit, and that he is lashed for a kazayit from all of them [combined]. (See Parashat Nasso; Mishneh Torah, Nazariteship 1.)

From the laws of the commandment is that which they, may their memory be blessed, said (Nazir 34b) that anything that comes out of the grape, whether it is the fruit or the refuse - meaning to say the zag which is the peel, and the chartsan, which is the seed that is inside it - is forbidden to the nazirite, and as it is explained in the Scripture. But behold, the leaves, the shoots, the vines and the immature berries (smadar), they are permissible; since they are not fruit and not refuse, but are considered like the tree. [This] and the rest of the many details of the commandment are elucidated in the tractate that is built on this, and that is Tractate Nazir.

And Rabbi Moshe ben Maimon (Rambam) wrote (Sefer HaMitzvot LaRambam, Mitzot Lo Taase 206), "The proof about each and every one of these five being an independent commandment - meaning wine, grapes, raisins, seeds and pits - is that, behold a person is liable for one [set of] lashes for each and every one. And [it is] like they, may their memory be blessed, said in the Mishnah (Nazir 34b), 'He is liable for the wine by itself, and for the grapes by themselves.' And they said [as follows] in Tractate Nazir 38b, '[If] he ate grapes that were damp and dry [along with] seeds and skins, and squeezed a cluster of grapes and drank [the juice], he is lashed five times.' And when they wanted to establish that the teacher that taught [these five sets of] lashes taught [certain prohibitions] and omitted [others] and that the nazirite is liable for more than five [sets of] lashes, they said, \'What did he omit? Behold, he omitted the negative commandment of "He shall not profane his word" (Numbers 30:3),' and they did not say he omitted, the prohibition of vinegar. And the reason is because he would not be liable for two [sets of lashes] for wine and for vinegar - as vinegar is prohibited for its essence which is wine, as we have said. And the content of the passage is as if it had stated that the essence of the prohibition of wine does not depart from it when [the wine] spoils, and as we mentioned above in its place (Sefer HaChinukh 368). And from that which is fitting for you to know is that these prohibitions of the nazirite all combine to [form] a kazayit and that we administer lashes for a kazayit." To here [are the words of Rambam].