ispindel hydrophobic coating ??

[picclock]

My ispindel seems subject to a lot of error caused by bubbles in the wort.
Has anyone tried coating it with a hydrophobic layer to encourage the bubbles not to stick ?

Best Regards

picclock

 

[hoppyscotty]

good idea but it will still read incorrectly. Best to just use it to monitor trend to establish how far through the fermentation you are.

 

[RoomWithABrew]

My ispindel seems subject to a lot of error caused by bubbles in the wort.

What do you mean by a lot of error?

 

[fluketamer]

I find mine is affected by the kreusen that it accumulates and never falls off

 

[picclock]

I only put mine into the brew after most of the kreusen has gone, just to make sure I get the end point right. if it has good kreusen then the ferment is good, so i don't need a hydrometer to tell me that. I take a reading just before pitching as a reference with a standard, very easy to break, hydrometer - 1060 for this one.

@RoomWithABrew
Lot of error - well look at the graph attached. Mauve line is iSpindel angle, red line is temperature (.fish tank heater). The large dip in angle reading is where I twisted it quickly to remove bubbles sticking to it. I reckon its still reading .035 higher than actual measurement, so 1022 last reading, I reckon is closer to 1018.

@hoppyscotty
I would like to know why you make that assertion. The only assumption I am making is that the measurement errors are caused by bubbles or debris sticking to the tube. From the graph you can see that the over the initial section the tube is becoming more buoyant, therefore it seems logical that bubbles adhering to the tube are the cause.

If i can remove that cause with a simple coating it should improve the device accuracy significantly.
I will do some tests and see what the results are.
Best Regards
picclock

 

[hoppyscotty]

Well it's my experience that he ispindel reads incorrectly. I have a few and all read accurately if you make up a water sugar solution of a specific gravity but in beer they are all way way out...not even close. I thin its several reasons..they probably sit close to the side and touch the side of the vessel and therefore the reading is affected. Once fermentation kicks off trub sticks to it affecting its angle and therefore reading. Its just too sensitive and affected by all that is going on inside the fermenter for it to return an consistent and accurate reading.

It gives a good trend that you can monitor and ultimately it doesnt really matter what the actual SG reading is duringfermentation if you can see a trend..all that really matters is the OG and FG which you can measure via more conventional means. You can judge your fermentation progress via the trend it returns. So in that regard its a powerful and very useful tool, but just dont take the actual numbers as being anywhere near correct.

 

[RoomWithABrew]

You will find that regardless of krausen on the ispindel it will still show the gravity and temperature trend.
Over time the gravity reading will become inaccurate due to minor movements of the sled in the petling, this either means you recalibrate or just accept it's not accurate and watch the trend.
I use my refractometer or hydrometer for my OG and FG

One of my ispindels I use in wine ferments and because wine has little krausen it is more accurate, but regardless the trend still

 

[gingerneil]

As others have said, trend is king. I find mine pretty accurate, to about 0.004-6 ish. Easily good enough to follow the trend and get a good idea if it's hitting around the FG that I'm aiming for. I always take manual readings for start/end and to determine my efficiency etc. as I brew.
Small bubbles on the side will make very very little difference, and within the expected error margin of the device. I wouldn't worry about any coatings.

 

[Agentgonzo]

I'm playing about with my fermenter and cooling/heating it.
I chucked the ispindel in there to give me a simple temperature readout.
The fermenter is just filled with 20L of tap water.
It's interesting to see how the SG changes with temperature. Roughly a 1 SG point different over a range of a few degrees.

 

[Stu]

There's a calculator here
https://www.brewersfriend.com/hydrometer-temp/

Some of the brews I do are quite happy at higher temperatures.
I guess as long as the OG and FG is consistent at temperature, then you're all good. But taking the FG after cold crashing could be interesting!