Menahot, Chapter Twelve, Mishnah Three
A minhah must consist of a tenth of an ephah of fine wheat flour. It must be accompanied by oil and frankincense. Our mishnah discusses what happens if one vows to bring a minhah that does not fulfill all of these requirements.
1) [If one said,] I take upon myself to bring a minhah of barley, he must bring one of wheat.
2) Of coarse flour, he must bring it of fine flour.
3) Without oil and without frankincense, he must bring it with oil and frankincense.
4) Half a tenth, he must bring a whole tenth.
5) A tenth and a half, he must bring two.
6) Rabbi Shimon declares him exempt, because he did not make his offering in the manner in which people usually make their offerings.
Section one: A minhah must come from wheat, not barley. If he vows to bring a barley minhah, he must bring one of wheat.
Section two: Similarly, if he vows to bring it from coarse flour, he must bring it from fine flour.
Section three: He must bring the minhah in its normal fashion, with oil and frankincense.
Section four: If he tries to bring less than the prescribed amount, he must bring the prescribed amount.
Section five: If he tries to bring 1 ½ tenths, what he has really done is vowed to bring one minhah and a half of a minhah. Since one cant bring half of a minhah he must bring two full menahot.
Section six: Rabbi Shimon says that the person is not liable to bring a minhah at all. His vow to bring a minhah does not count, since he didnt promise to make the offering in the way it is normally made.