Ive seen a few post about using an arduino to measure temps and what not for your beer but i was curious if i used an alcohol sensor such as (https://www.sparkfun.com/products/8880) this would it give me a semi accurate reading on the alcohol level of my beer while its brewing?
Arduino fg/alcohol sensors?
- Thread starter TauZero
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alien
Well-Known Member
I don't think those things are in any way accurate but I actually have a similar sensor so I might give this idea a try some time, just because I have no practical use for the thing! I suspect the calibration drifts over time. The other big problem is that you are supposed to "burn" the sensor in for 48 hours before you need to use it.
You could maybe use it to show when the beer has brewed dry when the vapour alcohol levels off.
You could maybe use it to show when the beer has brewed dry when the vapour alcohol levels off.
I did some looking at this once upon a time. What I determined (theoretically, at least) was that the easiest way to determine OG/FG with an Arduino or any other microcontroller was to use a pair of pressure sensors. If I remember the theory correctly, if you know the pressure at two points, and the distance between those points, you can calculate the density of the liquid.
-Medvitz
-Medvitz
alien
Well-Known Member
There was a kickstarter for an electronic hydrometer. The principle was not revealed but the prototype looked like electronic measurement of a floating hydrometer. The review I read indicated that measurements drifted over time so it needed recalibrating. The production model may be different but this is not something I would want to adopt early.
What if you added a pressure sensor to your fermenter, and an electronic valve that opened at a set pressure, to neutralize the pressure inside the fermenter.
When you start fermenting, you inject air with a large syringe, to see how much air is needed for the valve to open.
You then multiply the volume with number of releases, which after a ton of temperature corrections, tells you how much CO2 (alcohol) is produced ?
When you start fermenting, you inject air with a large syringe, to see how much air is needed for the valve to open.
You then multiply the volume with number of releases, which after a ton of temperature corrections, tells you how much CO2 (alcohol) is produced ?
dyqik
Well-Known Member
That would still vary with external atmospheric pressure, which varies by about the same amount as the gravity of beer during fermentation.
The two pressure sensor technique sounds plausible, but it does need pretty high accuracy, and probably temperature compensation for the sensors (I guess you need that anyway for the gravity calculation).
The two pressure sensor technique sounds plausible, but it does need pretty high accuracy, and probably temperature compensation for the sensors (I guess you need that anyway for the gravity calculation).
Yes, you would definitely have to use a difference-pressure sensor, and they often come with temperature compensation.
According to some quick calculations:
20L beer @ 5% ~ 1000g of alcohol ~ 1000g of CO2 ~ 500L of CO2
Which is a lot of CO2, so precision is less of a concern.
According to some quick calculations:
20L beer @ 5% ~ 1000g of alcohol ~ 1000g of CO2 ~ 500L of CO2
Which is a lot of CO2, so precision is less of a concern.
