"Bubble Logger" version 2 - Ferment controller for temp, and SG+acivity estrimation.

[kbaggen]

Dear All,
(https://github.com/kbaggen/Cheapfathers-Bubble-Logger)
I have worked a bit more on my fermentation Logger/controller, measuring "Temperature and Sound detection of CO2 bubbles" for NodeMCU (ESP8266). The software give an indicative SG estrimate based on S-airlock is used with a precise amount of water (4 ml)!
(First version was posted in this forum May2019 and can be find somewhere).


What I meassure is the Sound Blops pr. Min (SBM) comming when CO2 is released by a Sound detction module. If we look at the chemistry behind the metabolisms of fermentation of sugar by yeast cells, we see one part Alcohol generate two part CO2. Hence, CO2 is a direct measument of the alcohol production. The key issue is to measument this gas accuarate and precise. Hence, the need of sealed airtight tanks.

C6H12O6 ====> 2(CH3CH2OH) + 2(CO2) (+Energy)
Sugar ====> Alcohol + Carbon dioxide gas (+Energy)

Hence, by knowing the SBM and brew sieze (L) and other involving constants like pessure (p) and temperature (t) we can plot a curve of SBM/pt/L vs. the reduction in Gravity and generate a model or polynomial for the alcohol production based on our initial measument of Sound Blops pr. Min (SBM), se below graph.

This software give an indicative SG with an offset of +/- 2 SG untis if used in a airtight tank and an S-shaped airlock with 4 ml water in it!




Resume, of the Data behind there currently give an indicative SG by an error of +/- 2:



So, if a keen eye on placement/alingment of sound probe in airlock, 4ml water amount in s-arilock and a slow/controlled fermentation in a airtight fermenter and the use of the same calibrated sensor, it is possible to use CO2 as a SG measument though a 2nd degree poly.

You might have to re-calculate you own polynomial based on your sound sensor and its calibration. Hence, make 2-3 brews and take hydrometer measuments over the time compared to SBM/pt/L and update your polynomial. The same is likley needed if you change sound sensor.

All used data can be seen here: https://1drv.ms/x/s!An5QQQ1io7W7icIIRECfkWO0aTP8-Q?e=b4ph5j

Reason and what we will see
Knowing the yeast activity though CO2 bubble measurements over time including the start of decline, we can better foresee when the SG is close to FG, and better make decision on dry-hopping, temperature changes, etc.!

Brooklyn Lager Clone:



"Yoga Pils":



A more full description (diagram/equipment) and the code + dependicies can be seen at:
https://github.com/kbaggen/Cheapfathers-Bubble-Logger

/Best Regards Klaus

 

[eric19312]

This is cool...I don’t use s-type how hard to adapt to blow off tube in bucket?

 

[brewbama]

The only issue I see with relying on airlock activity (bubbles) is that based on my limited experience with a Bluetooth enabled constant read floating hydrometer, I’ve learned that fermentation can be happening in the beginning and end without any airlock activity whatsoever.

For example, I have a beer fermenting right now that dropped from 1.052 to 1.049 without the first hint of airlock activity (blowoff jar). Not even a pressure bubble in the hose yet SG was falling with temp constant.

Likewise, my previous beer finished after airlock activity stopped altogether. 1.012 down to 1.009 without any airlock activity.

To determine progress I didn’t have to constantly monitor the airlock in case I may miss a bubble. I simply pulled the blowoff jar hose up a bit to allow a portion of CO2 in the hose to escape and noted the level of the pressure bubble. By inspecting the bubble in the hose later, I could see the degree of pressure buildup. In the end the pressure bubble did not progress down the hose though SG continued to fall. I verified the fall with a very accurate calibrated finishing hydrometer.

I’ve always heard not to depend on airlock activity as a sign of fermentation and based on this evidence I can now provide an example.

 

[eric19312]

I've had mixed success with my Tilt. I have the older model with shorter battery life that may be the issue. I'm also trying to get the signal through the wall of a SS conical and then through a freezer wall. With a fresh battery I get a signal for a few days then it starts going wonky. In the end I've been watching airlock activity again and then taking a gravity sample when I think I'm close.

 

[brewbama]

They must have corrected the issues. I am five brews in on one battery in my recently acquired Tilt. I also have the repeater to boost the signal from the stainless fermenter in a fridge in a basement to me upstairs.

The repeater battery is rechargeable. It does require recharging after each ferment or will die mid way. I found out the hard way.

So far, I’ve found the Tilt to be very accurate. I especially like the logging function so I can monitor remotely using Google Sheets.

 

[kbaggen]

#2, the idea can be amendend to a tube making bubles in a blow-out by letting the mirc hang freely. But it changes the behaviour completly, and hence, all polynoimal/data change. So you need to make use of S-airlock, sorry If you look at github, you see one picture of my setup, and I sometime use a blow-out into other airtight blow-out container equipt with the s-airlock.........so that is also an option! Lastly, I just have higher headspace and run the sensor/s-aitlock directly on tank.

#3, the C02 produced stay in fermenter until the pressure overcomes the amount of water pressure in air-lock, hence, yes, something is happning before we see acitivty, but this is captured by the logger as the CO2 get relased later on. So, my experiance from the many brews I played with this, is the logger is a bit delayed in response hence, behind 1-2 SG points during fermentation. Secondly, the fall you saw of "1.012 down to 1.009 without any airlock activity" is most likely coz to leak and you fermenter not beeing airtight!

#4+5, Neither Tilt nor Ispindel is precise, and have issues as they get stuck in yeaste cage. Yes, I started this project as I couldent solder Ispindel and Tilt was just to expensive beeing only Bluetotth!

 

[kbaggen]

BTw.....if anyone wish to see how it looks at Ubidots:

Yoga Pils:
https://industrial.ubidots.com/app/...d/L_C6nHjPRmuJGg14DrfrSKe4oXY?datePicker=true

You, likely have to select the dates till "last 30 days"!

 

[Muchacho]

Glad to see you are back at it! And glad to hear that you are getting reproducible results for predicting gravity.

After your first round, I made a counter similar to your design and find it be a little easier to use (and make) that the ones that I have made with IR sensors. I like using bubble counters to give me a general sense of how rapid the fermentation is occurring and informing my hop additions and what not.

Your sensor works well with a blowoff tube in a bucket. However, unless the volume remains constant in the bucket and the tube remains in the exact same space, it is impossible to calculate gravity. Here is a pic that shows how I set up your design for a bucket/tube and on the other one you can see my IR gate. Both setups give me similar data about fermentation rate.

 

[kbaggen]

#8 Muchacho, some nice equipment there....cost a fortune over here! If I understand your setup, you let the bubles go into a tube there is placed in the blow-off?

I either have sensor directly on tank and try control the fermentation rate by cooling, or use a blow-out as shown if I know the fermentation is to "wild"!

 

[kbaggen]

Dear All,
lastes run is on:
https://industrial.ubidots.com/app/dashboards/public/dashboard/L_C6nHjPRmuJGg14DrfrSKe4oXY

I dry hoped it yesterday around 14.30, and a nice top is showen as the CO2 got released!