Brewometer kickstarter thoughts - digital bluetooth hydrometer

[user 204491]

Keep in mind the electronics were not made by Brewometer. My guess is they buy the board off the shelf. The temp swings must either be a faulty temperature sensor or the math they use to perform calculations. The probability of a several faulty sensors should be very low, so I believe something else is going on there.

Also, the published temp accuracy for the temp sensor is +/- 3 degs C.

Ahh, sorry, not sure what happened to what I typed there...

My temp readings were swinging +/- 20F and my gravity readings were swinging +/- 9 points, correlated to the temp swings.

I'll be getting one of my two new units in some wort this weekend and start logging things again to see if there's any difference.

 

[303Dan]

Keep in mind the electronics were not made by Brewometer. My guess is they buy the board off the shelf. The temp swings must either be a faulty temperature sensor or the math they use to perform calculations. The probability of a several faulty sensors should be very low, so I believe something else is going on there.

Also, the published temp accuracy for the temp sensor is +/- 3 degs C.

Wow, the sensor is only accurate to +\- 3 degrees C? I've been paying close attention to this thread because this sort of thing is right up my alley, but my primary concern with this (and the beer bug before it) is reasonable accuracy. For me to buy (and I'd be willing to pay more money if necessary), I think I'd need about +\- 1 degree F and +\- .001 on SG. To me, +\- 3C (5.4 degrees F) isn't even useful. But that's just what I'm looking for. I'm sure the information it provides can be useful.

And I understand they're trying to hit a price point and all that goes along with that. I'll stay tuned.

 

[pepindavid]

Wow, the sensor is only accurate to +\- 3 degrees C?

Not sure where that comes from, as their site says:

Q. How accurate is the Brewometer?

A. The specific gravity is accurate +/- 0.002.The thermometer is accurate +/- 2 degrees F (+/- 1 degree C).

 

[303Dan]

Keep in mind the electronics were not made by Brewometer. My guess is they buy the board off the shelf. The temp swings must either be a faulty temperature sensor or the math they use to perform calculations. The probability of a several faulty sensors should be very low, so I believe something else is going on there.

Also, the published temp accuracy for the temp sensor is +/- 3 degs C.

Not sure where that comes from, as their site says:

Q. How accurate is the Brewometer?

A. The specific gravity is accurate +/- 0.002.The thermometer is accurate +/- 2 degrees F (+/- 1 degree C).

I was assuming BrunDog was quoting stated specifications from the manufacturer of the temperature sensor component itself.

 

[BrunDog]

Well, the temp accuracy according to Punch Through is +/- 3: https://punchthrough.com/bean/guides/features/temperature/

But, accuracy and repeatability are two different things. The former assumes no calibration, the latter includes it. My guess is because we can calibrate, the resulting accuracy is much higher. So don't sweat this number too much.

 

[user 204491]

Interesting that the Bean site says they use the BMA250 chip which is designed to measure air temperature, not liquid temperature.

Would it be a logical conclusion therefore that they are not directly measuring the temp of the liquid that the unit floats in, but are instead measuring the temp of the air inside the Brewometer's protective casing?

That could explain why my new units seemed to be so far off on temp when I calibrated their gravity readings. They both needed adjusting by 6-8 degrees according to my Thermapen readings. Now I wonder if I'd allowed them to acclimate to their environment for 20 minutes or so if they would have gotten closer to the actual liquid temp. I'll try to give that a shot this evening if I have time and see what happens.

I also wonder if that could account for some of the temp swings we're seeing? Part of the unit floats above the surface of the water a bit, and air temperature changes much more rapidly than liquid temperature. I mean I don't think it would account for the +/- 20F swings I was seeing, but still makes me wonder.

 

[HLSheppard]

I've been generally enjoying mine since I put it into service last week. I was in such a hurry to start using it - I didn't bother to calibrate it (shame on me).

I have been noticing that the closer my phone is to the actual unit, the lower the gravity seems to be. Nothing huge, but when I get 20+ feet away the gravity will read 1.012 but as I walk within say, 5 feet it will go to 1.009.

I have been able to reliably repeat this for the last 3 days. I'm not really worried about it - just find it interesting.

Can any of you electronic engineer-types shed any light on this?

 

[beskone]

Interesting that the Bean site says they use the BMA250 chip which is designed to measure air temperature, not liquid temperature.

Would it be a logical conclusion therefore that they are not directly measuring the temp of the liquid that the unit floats in, but are instead measuring the temp of the air inside the Brewometer's protective casing?

Exactly this. The chip / probe are inside the plastic casing, so it's measuring air temp inside the casing which is affected by the temperature of the liquid it's floating in.

So if you pull a brand new one out of a box that's sitting in 85º ambient air, throw it in a 65º carboy and immediately calibrate it for 65º you're gonna have a bad time.

Best to put in in water and let it equalize for at least 30 minutes before calibrating I would guess.

 

[user 204491]

Exactly this. The chip / probe are inside the plastic casing, so it's measuring air temp inside the casing which is affected by the temperature of the liquid it's floating in.

So if you pull a brand new one out of a box that's sitting in 85º ambient air, throw it in a 65º carboy and immediately calibrate it for 65º you're gonna have a bad time.

Best to put in in water and let it equalize for at least 30 minutes before calibrating I would guess.

Yep, I bet that is exactly what's going on. Tonight I will clear my previous calibrations and try again after letting it sit in the water for 30 minutes or so to acclimate.

I do still wonder if this is what is causing the temp anomalies since part of the unit floats above water and it takes time for the air inside the unit to adjust to the temp of the wort.

I never heard back from the developers after Thursday last week, so I'll drop them a note and see what's up.

 

[jpakstis]

I did some fooling around with it/getting acclimated with it over the weekend in anticipation of brewing this weekend and I gathered that the temp is really the air temp inside the casing since I noticed it reacting slower to changes in water temp than my Thermapen's reading, but wasn't too far off (around 3-4 degrees).

 

[CascadeOK]

It would be nice if it used a stainless steel bottom cap with an actual probe on the inside of the SS cap. I'd rather have true liquid temps and it would be a fast calibration and cut down on their temp related customer service issues.

A BrewPi integration for dummies would also boost sales a bit.

 

[Carlscan26]

It would be nice if it used a stainless steel bottom cap with an actual probe on the inside of the SS cap. I'd rather have true liquid temps and it would be a fast calibration and cut down on their temp relates customer service issues.



A BrewPi integration for dummies would also boost sales a bit.

Great points!!

 

[user 204491]

FWIW I did hear back from the developer on measuring air temp as opposed to liquid temp. Here is what they had to say:

You are correct on the temp. The device needs to come to equilibrium to calibrate/test. It takes 15-30 minutes depending. I would clear the temp calibration you made, let it sit in a known temp solution then check again and recalibrate as needed.

 

[pepindavid]

Interesting. Could the difference in temp between the interior of the device, the air in the headspace and the beer somehow affect the way the device is floating, hence affecting the "tilt" and therefore the gravity calculation? That would explain why I was getting some very weird gravity readings during temperature changes (e.g.: while cold crashing).

 

[user 204491]

If you take a look at my tracking graph here, you'll see that I had a number of unexplainable temp readings throughout my fermentation, and with each one the gravity also swung in correlation with the temp. I saw the most craziness going on after I started my cold crash as well.

I pointed this out to the developer, and he said they discussed it at length at their meeting last week, but they could not explain it. He said they received another defective unit like mine, and they will be testing both out to see what could have caused the problem.

I'll be getting my replacement unit in some fermenting beer this weekend and my second unit going next weekend, so I should be able to report soon if this first one was just a complete anomaly, or if there's some sort of larger problem at hand.

So far the folks I've been corresponding with have been very nice, and I'm sold that they will stick to their word and refund or replace any units if people are not satisfied with them.

 

[BrunDog]

I would certainly expect a time lag between the liquid temp change and the sensor reading. But the unit is Amosa completely submerged so I expect the conductivity through the case to be fairly effective. Would be interesting to see how/if cold crashing screws up the readings in the short term.

 

[boat_eggs]

Learn from my mistake and dont chuck one of these in during the sanitize step on a conical. Mine got stuck in the elbow in the bottom Im glad I got a pair, the other one is happy. Once I get a always on tablet Ill pay attention to the gravity/temps swings and compare them to my BCS temp probes.

 

[NeoBrew]

Wouldn't measuring the temp inside the capsule lead to errors from the heat of the electronics in there?

 

[BrunDog]

There is some quiescent heat generated by the electronics but it is too negligible to make any difference. The battery life claim is 3-6 months, so the power being dissipated is practically nothing.

I don't think we should witch-hunt the temp sensor. It is integrated with the accelerometer and is a reasonably quality piece. The question is how they implemented them mathematically.

 

[user 204491]

I would certainly expect a time lag between the liquid temp change and the sensor reading. But the unit is Amosa completely submerged so I expect the conductivity through the case to be fairly effective. Would be interesting to see how/if cold crashing screws up the readings in the short term.

If you take a look at my graph here, the point on 4/24 @ 4:51 AM is when I started my cold crash. You can see that it did not behave very nicely.

It was sitting at 65 when I kicked in the cold crash, and the first thing it did was jump up to 78, then dropped all the way down to 24, and was all of the place for the next 4 days.

Again, this was with my "defective" unit which has been replaced, but I haven't had a chance to try out the new one yet.

I had another exchange with the developer last night, and I asked him about the bit of the Brewometer that was exposed to air, and he told me that in their testing they had not experienced this causing any problems with the temp readings. He also said they are working on a new unit using an IR temp sensor.

 

[pepindavid]

FWIW, my temp readings were ok while cold crashing (they may have been slightly different from the beer itself until equilibrium was reached, but nothing too weird). It's the gravity reading that became wrong: it had been sitting between 1.014 and 1.016 (which was fine, as the hydrometer at bottling showed 1.015), but it went as low as 1.007 during cold crash, which was obviously wrong.

I don't know much about "floating science", but wouldn't temperature differences affect the pressure (within the device and the headspace, if my High School chemistry is still right)? And if the pressure is affected, could it affect the "floating" of the device, therefore affecting the tilt? Now that I think of it, though, the weight of the air within the device shouldn't change; just the volume and the pressure.

Looking forward to see if my replacement will act differently!

 

[BrunDog]

Density is weight per volume. Neither change so density remains the same.

That said, regular glass hydrometers are affected by temperature. I assume this is because the liquid becomes slightly more dense with decreasing temperature. I can't imagine the rules are different for this device, so the temp sensor *should* use the temp in its calculations.

Hey has the developer been informed of this thread? It would do them well to be present here.

 

[TaylorBrewed]

So my unit stopped sending information to the cloud last night around midnight. I suspected it might have been battery or my phone that I use to grab this information died. I went to my basement this morning where my chamber is and it was still sending information to the phone. I emailed the developers to see what they suggest. I un-clicked the box to start sending information to the cloud and then re clicked it hoping that it would start sending information again but no luck. Has anyone experienced this and what might you suggest to try while I'm waiting to hear back from the developers. Thanks

 

[beskone]

So my unit stopped sending information to the cloud last night around midnight. I suspected it might have been battery or my phone that I use to grab this information died. I went to my basement this morning where my chamber is and it was still sending information to the phone. I emailed the developers to see what they suggest. I un-clicked the box to start sending information to the cloud and then re clicked it hoping that it would start sending information again but no luck. Has anyone experienced this and what might you suggest to try while I'm waiting to hear back from the developers. Thanks

ya mine does this, i think it's flaky wi-fi in the garage but I'm not 100% sold on that. Gonna have to verify next brew.

 

[enkamania]

So my unit stopped sending information to the cloud last night around midnight. I suspected it might have been battery or my phone that I use to grab this information died. I went to my basement this morning where my chamber is and it was still sending information to the phone. I emailed the developers to see what they suggest. I un-clicked the box to start sending information to the cloud and then re clicked it hoping that it would start sending information again but no luck. Has anyone experienced this and what might you suggest to try while I'm waiting to hear back from the developers. Thanks

My internet has gone out a couple of times. I shut off my tablet and restart the program, that did the trick.

 

[TaylorBrewed]

That must had happened during the night. Your solution fixed it. Thanks

 

[jmark]

Finally racked my first beer using the brewometer this afternoon. FG was 1.012 based on my hydrometer reading which was just about the same as the brewometer (1.010). For tracking gravity, I think this tool does the job - I think there are issues with temps though but I use brewpi for tracking and controlling temperature, so that doesn't bother me.

 

[user 204491]

Hey has the developer been informed of this thread? It would do them well to be present here.

Yeah, I pointed this thread out to them a couple of times in our correspondence, and I believe they read at least part of it, as they mentioned to me how exciting it was that people were already hacking the device.

I also experienced the unit stopping logging several times during my first trial run. It would seem to go quiet for sometimes over an hour, and then have rapid fire updates all within seconds of each other.

I mentioned that to the developer, but they did not have an explanation.

I'll point this thread out to them again and ask them to come join the fun!

 

[BrunDog]

For anyone interested, you can pick up a 7" Amazon Fire for $40 through Saturday. I almost clicked the "buy" button but then I realized I don't *really* need a tablet mounted to my fermentation freezer...

 

[AF1HomeBrew]

You guys are having too much fun, so on 4/22 I decided to purchase one too. Last night I received an email with a shipment notification. I should receive mine this coming Monday.