Ideally 17. It doesn't have to be left over. You can just open a beer and then drink the rest.
And obv. best not to use any beer that had been drunk from the bottle/ can etc.
@deleted started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Ideally 17.
It doesn't have to be left over. You can just open a beer and then drink the rest.
And obv. best not to use any beer that had been drunk from the bottle/ can etc.