Hydro-boy

[Brewin_Bob]

Subscribed ...

What is the diameter of the ball? I ask because I see how it could be easily placed into and removed from a ale pale or conical but not a carboy.

While using RFID tags is more time efficient and convenient for the brewer, is it more cost efficient than having the inputs hard-wired? Referencing concept 5, would a thin, food grade, flexible tubing be enough to meet the requirements of:

1 - must be flexible enough to NOT restrict free floating
2 - must NOT leach anything into fermenting wort
3 - must NOT interfere with the duties of the yeasties

Thanks.

 

[pizzaman]

Typical hydrometers float on the surface, and the level they float at is determined by differences in the density of air, and the density of the wort. It looks like your donut isn't floating, it's submerged. There is no wort density difference above and below it, it's the same above and below (for all practical purposes), so the ring will sink to the bottom, or float to the top. You COULD develop a ring that would be neutrally buoyant, but it would only be neutrally buoyant at one SG. Then it would sink all the way to the bottom as soon as the SG dropped at all.

I was unaware of this, but it makes sense the way you described it. Whatever is acting as the hydrometer would need to be partially above and below the wort, be long enough to move up and down as the gravity changes, and not be effected by the krausen being created. This should prove fairly tricky to overcome...the first thing that comes to mind is using a material for the hydrometer tube which would be able to resist krausen build up so there would be no worry about it being weighed down...nothing comes to mind at the moment. Perhaps a complete re-think is in order...

 

[GreenwoodRover]

What about reversing the sensors.
The floater is the control, and then mount one to the top of an air entrained capsule and have it read the distance above the wort line....

 

[pizzaman]

What about reversing the sensors.
The floater is the control, and then mount one to the top of an air entrained capsule and have it read the distance above the wort line....

It would be easy enough to simply have a donut shaped floater around a hydrometer tube, unfortunately it has been determined by previous testing that simply leaving a hydrometer tube inside a fermentation vessel is inaccurate because the krausen will build up on the tube and weight it down. This is where I came up with the idea for the balls, where one would float at the liquid line, and the other would(I assumed) float at a depth determined by the gravity. Unfortunately it was pointed out to me that hydrometers need to be partially submerged, and partially sticking out of the liquid in order to measure the difference in the density of the liquid and the air above it.

Two ideas I have to overcome this are:
1) Use water as the control variable, rather than air. I'm not sure of the mechanics of this, but basically it would require a small vessel filled with water, and some way to compare the density of the water inside to the wort outside. I have a few loose ideas floating around my head of how to accomplish this, but no clear thoughts on it yet at this point.

2) Use the weight of the container to determine gravity. This would require the use of a digital scale underneath the bucket/carboy, and a small floater inside the bucket. The scale would be custom built, with an RFID reader built into it to determine the height of the floater in order to calculate the volume of the wort. The mass of the empty bucket would be programmed into the scale by the user before first time usage, and that would be used to calculate the density. This of course would be a much more expensive approach, and you would basically have to purchase one for each fermentor you own. This isn't ideal, but it is an idea to build off of.

 

[hughmac]

I like both ideas, water instead of air and I really like the idea of just weighing the whole thing. So elegant, and should be ridiculously accurate if the scale is up to it. Now I just need a couple of 50lb scales with gram accuracy.

For a 5gal batch, what would the weight difference be for 1.050 > 1.010 or something? What kind of accuracy do we actually need? I'm thinking the weight drop would be around 1.75lbs, or 28ish oz (water (1.000) = 8.345404lbs/gal = 41.73lbs/5gal, a 1.050 wort would be 43.81lbs (I think?), a 1.008 wort would be 42.06 ... a 27.94oz drop) ... so even oz accuracy would be usable? Very close to 1.5 points per oz, not bad. That's if I'm doing the math right. A big balance scale, or pulley and weights, would be cool too, and maybe DIYable.

Hmm ... fishing scales usually have oz accuracy and 50lb limit, so could work for a 5lb batch I think (depending on the fermenter weight).

What is the accuracy of the RFIDs? If they are very accurate, the thin-wire hydrometer tip above the water wouldn't have to go too high.

I can't stop thinking about this. Damn you pizzaman.

 

[Jballard]

fda approved tubing

you can look into other materials as well, slide the wires in to the tubing.
tubing can also be used to keep the entire device stationary within the fermenting device.
with wires you avoid the placement or batteries inside your bucket, in a severe failure you could have battery acid in your wort.

also adds the capabilities of having a small dc motor to knock off crud.

also having your hand held device connecting at the top of the vessel by a wired connection usb maybe could also bring the cost down.

 

[hughmac]

Cheapskate Gravity Scale!

The more I think about it, the less I think that it will work. While the gravity of the beer goes down, the quantity of yeast goes up, other stuff is in there, etc. Hard to get accurate values all around.

I'll probably give it a shot sometime, just for grins, and see if there is any correlation between weight and gravity.

Wish I just had a big, uber-accurate scale to just set the whole she-bang on.

 

[pizzaman]

Fill your carboy with distilled water. Mount a laser pointer to the upper side of a carboy so that it is hitting the water line at exactly 45°. Take a clear piece of tape and stick it to the carboy on the opposite side from the laser, so the light is hitting the tape. Mark the light, then move the laser to different angles and mark the corresponding spots on the tape. Then dump out the water and you've got yourself a built in refractometer. Sorry, no pic this time.