Wash the tower and clear the drip valve
DailyGlass and a slow valve are where cold brew grows things.
What you need
- Bottle brush long enough for the tower. Washing-up liquid. Spare paper filters, or a cloth filter kept wet.
What goes wrong
- Letting a cloth filter dry out, which locks the trapped oils in and taints every later brew. Leaving the valve half-open to dry, which lets it stiffen. Cleaning the glass with anything abrasive.
The procedure
- Wash all three glass chambers with hot soapy water within a few hours of finishing the brew. Cold brew residue sours faster than it looks.