My own past flute teachers gave me conflicting advice about how much the flute headjoint should press into the lower lip. One would pull on the crown of my flute while I played to make sure it came away from my lip with no resistance. Another would push the headjoint more firmly into my face as I played. (I improved under both teachers’ approaches.)

I got curious about it recently and looked up what some flute pedagogues have had to say. I’m presenting my findings here without taking a personal stance (yet).

It’s a little tricky to parse some of these, since many speak in terms of avoiding too much pressure, but don’t clarify whether that means to use as little pressure as possible or some moderate amount of pressure.

In the avoid-too-much-pressure camp:

A very important point to remember is never to force the mouth plate against the lower teeth as such forcing will limit the amount of flexibility after the embouchure has been developed.

James Pellerite: “Improving Tone Production in Flute Performance,” in Woodwind Anthology, volume I, 1999 edition. Northfield, Illinois: The Instrumentalist, 1999, p. 11. Article originally printed in The Instrumentalist in 1953.

Do not press the head joint hard against the lips. Control of the tone must come from the lips themselves, not from pressure.

George Waln, “First Flute Lesson,” in Woodwind Anthology, volume I, 1999 edition. Northfield, Illinois: The Instrumentalist, 1999, p. 25. Article originally printed in The Instrumentalist in 1957.

“The chin is, of course, an aid in support, but it must not be depended on for support, since pressure against the jaw will seriously disturb the embouchure.”

Edwin Putnik: The Art of Flute Playing, revised edition. Miami, Florida: Summy-Birchard Inc., 1970, p. 7.

In order to correct this problem [sharpness/pinching], the student should be certain that he is not pressing the flute against his lower lip, but rather thinking of the flute as resting lightly against the lip…

Mary Jean Simpson: “Flute Intonation Trouble: Spare Not The Rod,” in Woodwind Anthology, volume I, 1999 edition. Northfield, Illinois: The Instrumentalist, 1999, p. 117. Article originally printed in The Instrumentalist in 1972.

Do not press the flute too tightly against the chin because too much pressure will alter the tone and pitch.

Kathleen Goll-Wilson, “Erratic Intonation in Flute Sections,” in Woodwind Anthology, volume I, 1999 edition. Northfield, Illinois: The Instrumentalist, 1999, p. 661. Article originally printed in The Instrumentalist in 1992.

Excessive pressure against the chin should be avoided.

William Dietz, Jerry Kirkbride, Hal Ott, Mark Weiger, Craig Whittaker: Teaching Woodwinds: A Method and Resource Handbook for Music Educators. Belmont, California: Schirmer, 1998, p. 174. Note: Hal Ott is the flutist among the authors, so this presumably reflects his opinion.

…the flute should rest lightly against the chin in order to leave the lips free and flexible.

Nancy Toff: The Flute Book: A Complete Guide for Students and Performers, third edition. Oxford University Press, 2012, p. 94.

[Common problems:] Too much pressure into the lip. The teacher should be able to tap the flute off of the lip with very little effort. … [for piccolo:] Too much pressure into the face, especially upper register. Excessive pressure makes high notes much more difficult if not impossible.

Charles West: Woodwind Methods: An Essential Resource for Educators, Conductors, and Students. Delray Beach, Florida: Meredith Music Publications, 2015, p. 17.

These are the ones I could find that seemed to advocate for at least some pressure, although neither is explicit about how much:

Students should keep in mind the three points of pressure… [including] the lips pushing out against the flute…

John Knight, “Flute Intonation,” in Woodwind Anthology, volume I, 1999 edition. Northfield, Illinois: The Instrumentalist, 1999, p. 529. Article originally printed in The Instrumentalist in 1989.

“Keep a relaxed embouchure, but place the flute firmly on the chin.”

Michel Debost: “Basics of Flute Playing,” in Woodwind Anthology, volume I, 1999 edition. Northfield, Illinois: The Instrumentalist, 1999, p. 632. Article originally printed in The Instrumentalist in 1991.

John Knight is the only author to speak in terms of the lips putting pressure on the flute, rather than the reverse.

In any case, among the sources I consulted, there seems to be some consensus that pressure of flute against lip should be light, or at least not “excessive.”