A brown bag session is a talk given over lunch, with the audience eating while they listen. The name comes from the paper bag people once carried a packed lunch in, and it carries a promise about the format: informal, short, no preparation expected of the audience, and no ceremony.
Where the name comes from
American workplace usage, from the plain paper bag a packed lunch was carried in. A brown bag meeting was one you brought your own lunch to, as distinct from one where lunch was provided, and the distinction mattered because it signalled that the session was informal and not an occasion.
The name still does that work and it is the reason the term survives. Calling a session a brown bag sets an expectation: nobody will be judged for eating, the speaker has not rehearsed for a fortnight, and leaving early is fine.
Where lunch is provided, the name is technically wrong and almost nobody minds. What would be wrong is calling something a brown bag and then running it as a formal presentation, because the name has promised otherwise.
What fits in the slot
Twenty-five minutes of talking, reading the chart. That is considerably less than a conference talk, and the difference is not solved by talking faster.
What suits it is one idea with one example: something the speaker did last month, a tool they started using, a problem they solved. What does not suit it is a survey, anything requiring the audience to follow along on a laptop, or anything with a build-up.
One idea, one example, and let people eat.
Running one
Practical things, most of which are about the room rather than the talk. People arrive over ten minutes, so the first five minutes should not carry anything essential. Eating is noisy, so a speaker needs to project or be amplified. And the lights stay up, because a darkened room over lunch produces exactly the result it sounds like.
Slides need to be readable from the back with a sandwich in hand, which in practice means fewer of them and larger text than a conference talk would use.
Recording is worth doing and rarely done, because a brown bag is frequently the only place a piece of internal knowledge gets explained out loud by the person who knows it.
Getting people to come
The obstacle is never interest, it is that lunch is the hour people use for everything else. What works is a title that names the subject rather than the speaker, sent far enough ahead that it lands in a calendar rather than in a corridor, and a standing slot: the same day each fortnight, so nobody has to decide whether this one is worth it.
What does not work is making attendance expected. A brown bag that has become compulsory is a meeting, and the format’s entire value is that people are there because the subject interested them.
Why the format persists
Because it costs nothing. No room booking beyond a lunch hour, no travel, no budget, and a speaker who needs an afternoon of preparation rather than a month. That makes it the format where most people give their first talk of any kind, which is its real function.
A brown bag is also the natural rehearsal for a conference talk, and organisers of local user groups are usually glad to host one. That path is set out on first-time speakers.
What it is confused with
A lunch and learn. The same format with the lunch provided and, usually, a vendor providing it. The difference is who paid, and it changes the content more often than anybody admits.
A lightning talk. Five minutes with a hard stop, in a programmed block. See lightning talks.
A workshop. Hands-on, longer, and needing helpers. Nothing about a lunch hour supports it.
The rest is in the glossary.
Questions
What is a brown bag session?
A talk given over lunch with the audience eating while they listen. The name comes from the paper bag a packed lunch was carried in, and it promises an informal session: no ceremony, no rehearsal, and leaving early is fine.
How long should the talk be?
About twenty-five minutes inside a fifty-minute slot. People arrive over the first ten and leave in the last few. A forty-minute conference talk brought to a lunch hour has to lose a third of itself, and the third usually cut is the examples.
Does lunch have to be brought rather than provided?
Originally yes, and almost nobody minds now. What matters is the expectation the name sets: calling something a brown bag and then running it as a formal presentation breaks a promise the title made.
What subjects suit it?
One idea with one example: something done last month, a tool recently adopted, a problem solved. Surveys, anything needing the audience on a laptop, and anything with a long build-up all fail in the slot.
Why does the format persist?
Because it costs nothing: no room booking beyond a lunch hour, no travel, no budget, and an afternoon of preparation rather than a month. It is where most people give their first talk of any kind, which is its real function.