I have a pretty good internal clock but like all brewers, keeping track of
time, especially when talking to the public can be a challenge. Boil and mash
times are relatively long and it is easy to get distracted. It is, therefore,
important to objectively measure not just experience and guess about
time. Unfortunately, like most other instruments, watches and clocks are very
expensive hand-made luxuries in the 18th Century and if a Journeyman Brewer had one, it was likely the second most expensive thing he owned[1].  Most craftsmen would out of necessity use more rudimentary means of measuring
time.

If you lived in the city, there are harbor bells and town clocks like the
one in the Pennsylvania Statehouse[2] with bells that ring on the quarter hour. This is generally good enough for a brewery so all you really need do is pay attention. If you cannot hear the bells, a poured (not dipped) candle soaked overnight in salt water the dried so that it burns in a dripless manner[3]
makes a pretty good time piece. If it is protected from drafts, such a candle
will burn in a constant and predictable rate so to measure time, one need only measure the change in its length. Finally, of you can observe the shadow from a tall structure like a church steeple, the passage of time can be estimated by how these shadows move, like a sundial. If you are not lucky enough to live in the city, you will need to rely on the position of the sun.

The earth rotates at a constant speed so the distance the sun travels across
the sky each minute is also constant. Yes, the path that the sun takes is
different from day to day and season to season and this is why the days are
longer in summer than in winter but the absolute distance the sun travels each
minute remains unchanged. You can, therefore, measure from the same location the position of the sun above the horizon or some other fixed point at two different times and the distance the sun has traveled will be proportional to
the time elapsed. Using my hands at a location near Philadelphia, I can
estimate that when the sun has traveled the distance in the sky that I would
observe as the width of my finger (2cm) on an outstretched arm (~0.9m) is
roughly 15 minutes with surprising repeatability and accuracy. Not a bad
chronometer and always handy.

There are other means, and of course, most reenactors carry pocket watches
because in truth we live in a time obsessed century but its good to know the
basic means as well.

[1] Average cost for a basic watch sold in Philadelphia in 1760 would have been about 12£ 5s. That’s almost a year’s wage!

[2]Independence Hall

[3] The salt makes the outer few millimeters of the candle have a higher melting
point than the center making the candle “dripless.”