Metabolic Rate of Yeast per Air Lock

[ptech]

the air lock was blowing a bubble on the second day at a rate of 59 bubbles per minute. On the third day the rate was half of that at 29 bubbles per minute. I know the bubbles are the CO2 waste of the yeast after they metabolize the sugars. So I suspect this is a good indicator of the metabolic activity that I can't see in the bucket.

1) Should it have slowed down that much by the third day?

2) can the bubble rate in the airlock be used to know when it's done ? as in, it's done when there's no more bubbles in the airlock?

thanks,
ptech

[Dnderhead]

YES and YES

[cornsqueezer]

can the bubble rate in the airlock be used to know when it's done ? as in, it's done when there's no more bubbles in the airlock?

Yes, unless your ferment stalls. When bubbles stop or slow way down just taste it and make sure its dry and not sweet before you run it, cause if it's sweet then you need to find what caused it to stall.

you need to buy a mash hydrometer[ they are not that expensive ] and take a beginning gravity of the wash/mash and when it stops bubbling take another gravity reading [ should be 1.000 or lower to be finished] if its above that you still got fermitable sugars and it has stalled for some reason.

[ptech]

you need to buy a mash hydrometer

I have one and it said 1.030 at the begining on the following recipe;

6.3 Lbs corn
1.25 Lbs malted barley
1.5 Lbs sugar
5 gal water

The air lock was bubbling at a rate of;
1st day 59 bubbles per minute
2nd day 29 per minute
3rd day 12 per minute.

I just have no clue if 1.030 is the expected number for this batch.
The starting PH was 5.6
the starting temp was 64F (the temp after 3 days is 71F)

[maheel]

i prefer cling wrap

saves washing the bubbler / air locks

[Ghost]

Since I have been fooling with all of this - I have learned that taste is one of your best indicators. While the meter readings will give you a great clue as well I have had a wash finish and the meter not read below 1.00 due to the solids (corn) floating around and throw it off a tad. Taste that wash - should taste like a very dry wine. Dip a clean couple of fingers in there, hold them in the air and it shouldnt be sticky at all. Good luck, you are getting there.

[ptech]

Two bubbles per minute ... soon my cherry will pop

Ptech

[ptech]

Today is the end of the seventh day of my very first fermentation ever...the bubbling rate of the airlock is now 100 Bubbles per hour (I just converted that from 5 bubbles per 3 minutes). I'm sure some day I won't need to count the bubbles with my stop watch but on my very first fermentation I'm just not sure and no confidence yet.

What does it mean "...when bubbles slow way down...".
Is 100 per hour considered slowe'd way down? or is two bubbles per hour considered slowe'd way down. What about one bubble every 4 hours? I'm sure other stillers don't stare at the Airlock for 60 minutes non stop to make sure they don't miss any bubbles...do they?

What if 3 days from now (the tenth day), the Airlock is still producing bubbles at ten (10) bubbles per hour...that means the yeast are still converting sugars right?

this recipe is
6.3 Lbs corn
1.25 Lbs malted barley
1.5 Lbs sugar
5 gal water
yeast

kind thanks,
ptech

[Ghost]

whats the SG ? What does it taste like? I dont watch bubbling airlocks as much as I use to - once it kicks off I leave and forget it for a few days and then check it out. The taste is a huge indicator, super dry and she is done. Sweet and its not finished. I usually know when it is producing maybe one bubble every 30 seconds.

Bubbling is not a great indicator as it could simply be degassing trapped C02 and not actual fermentation. Take the lid off and take a taste if you dont have a SG meter. Much like distilling let your nose and taste buds be your guide.

[bellybuster]

At this point the bubbles mean very little if anything at all, there is no ratio of bubbles/fermentation. Even temp differences can produce bubbles in your airlock. The wash is just releasing gasses it produced during fermentation, mostly CO2.
You would be best served by original and ending specific gravity readings, it is the only way to know what is going on.
Without SG readings you can only assume/guess that your fermentation is done. If you purchase an hydrometer now you can at least know that your wash has fermented down close or less than 1.000 and assume it is finished

[cornsqueezer]

At this point the bubbles mean very little if anything at all, there is no ratio of bubbles/fermentation. Even temp differences can produce bubbles in your airlock. The wash is just releasing gasses it produced during fermentation, mostly CO2.
You would be best served by original and ending specific gravity readings, it is the only way to know what is going on.
Without SG readings you can only assume/guess that your fermentation is done. If you purchase an hydrometer now you can at least know that your wash has fermented down close or less than 1.000 and assume it is finished

+1 bellybuster without knowing og & fg it's hard to know what the ABV% of the wash/mash is.

[ptech]

1.030 was starting & the ending was ~0.990