A brewday is a program. You write it before anything is hot — the mash rests, the
boil, when each hop charge goes in, how cold the fermenter runs. Then you press RUN
and find out what the brewhouse thinks of your program.
1
Write the mash. Rest temperature decides how fermentable the wort is. β-amylase works near 62 °C and makes maltose the yeast can eat. α-amylase works near 70 °C and makes dextrins it cannot. Both die above 78 °C.
2
Time the hops. Bitterness is alpha acid isomerised by boiling, and it plateaus near 60 minutes. Aroma oils are volatile and boil off, so aroma comes only from the last few minutes and the whirlpool.
3
Set the fermenter. Cool ale fermentation at 18–19 °C is clean. Above 24 °C you get banana and solvent. Lager yeast wants 10–12 °C.
4
Then steer it. The tun loses heat, the grain bed compacts, the hot break climbs the kettle, the fermenter runs away. Four buttons, live, while the clock runs.
DRAG orbit the brewhouse H or SPACE hold to heat C hold to cool E ease the bed K knock the foam down 1 2 3 clock speed R restart