I notice a lot of people saying Airlock activity is meaningless. Quit it, right now, youre scaring the children. Beginners are likely to get confused when you deny them a common sense observation and try to force them into the cult of specific gravity.
Dont get me wrong, I have a hydrometer and Im not afraid to use it, though I did go without one for a couple of years. What Im saying is that observing airlock activity is a useful indication, as well as providing hours of entertainment watching the bubbles.
C6 H12 O6 → 2 CH3 CH2 OH + 2 CO2
glucose yields ethanol plus carbon dioxide.
This is what were doing, remember? My point is that the volume of CO2 indicates the speed of the reaction. Would you drive a car watching the odometer but ignoring the speedometer? Its useful to know how fast youre going as well as how far.
Heres how to use this wonderful tool:
No bubbles indicates the reaction is very slow or zero. This could mean the fermentation hasnt started yet, its stuck or done.
The interval between the bubbles is a direct indication of the volume of CO2 being produced. It could tell you youre speeding up (more bubbles) or slowing down (fewer bubbles). In a special case, if its spitting sanitizer, youre way too hot.
For example, a batch I just pitched two hours ago is showing slight pressure despite it sitting on ice. This tells me there is enough activity to offset the reduced pressure of the cooling air in the headspace.
Someone is probably going to tell me thats bad practice, but Ive found the yeast dont mind being slowly cooled in the lag phase. Its a big timesaver. The problem is my tap water is 25ºC (77ºF), so to cool below that requires either a bag of ice or a huge air conditioning bill. Plus I get better control with ice-water than cool air.
One more thing; people tell me they prefer the three piece airlock over the classic double bubble because its easier to clean. Clean what? Carbonated water? The double bubble is more fun to watch and gives a more precise indication. Slainte
Dont get me wrong, I have a hydrometer and Im not afraid to use it, though I did go without one for a couple of years. What Im saying is that observing airlock activity is a useful indication, as well as providing hours of entertainment watching the bubbles.
C6 H12 O6 → 2 CH3 CH2 OH + 2 CO2
glucose yields ethanol plus carbon dioxide.
This is what were doing, remember? My point is that the volume of CO2 indicates the speed of the reaction. Would you drive a car watching the odometer but ignoring the speedometer? Its useful to know how fast youre going as well as how far.
Heres how to use this wonderful tool:
No bubbles indicates the reaction is very slow or zero. This could mean the fermentation hasnt started yet, its stuck or done.
The interval between the bubbles is a direct indication of the volume of CO2 being produced. It could tell you youre speeding up (more bubbles) or slowing down (fewer bubbles). In a special case, if its spitting sanitizer, youre way too hot.
For example, a batch I just pitched two hours ago is showing slight pressure despite it sitting on ice. This tells me there is enough activity to offset the reduced pressure of the cooling air in the headspace.
Someone is probably going to tell me thats bad practice, but Ive found the yeast dont mind being slowly cooled in the lag phase. Its a big timesaver. The problem is my tap water is 25ºC (77ºF), so to cool below that requires either a bag of ice or a huge air conditioning bill. Plus I get better control with ice-water than cool air.
One more thing; people tell me they prefer the three piece airlock over the classic double bubble because its easier to clean. Clean what? Carbonated water? The double bubble is more fun to watch and gives a more precise indication. Slainte