ISpindle

[Danny-CIPA]

Morning all,

I recently got myself an iSpindle to take away the need of pulling off samples for readings. First off it's an awesome little bit of kit for the price when linked to your brewing software, mine being brewfather.

However I bought it "calibrated" and have just trusted that it was spot on. I've noticed my last 2 brews have finished quite a bit under what brewfather was predicting. Brewfather was saying around 1.014 and both times it came out around 1.006. Initially I put it down to potentially over pitching but on my last brew I definitely didn't over pitch and still the same thing.

On my brew yesterday I noticed my OG was about 7 points below where I was expecting when the iSpindle kicked in, confirmed by additonal hydrometer reading being higher, so I am almost positive its calibration of my iSpindle that is off. I've pretty much confirmed it by taking a finished sample of my last brew and the floating hydrometer giving me a reading significantly closer to what brewfather was initially suggesting.

So my question is for those that have one of these iSpindles would you just offset the reading in brewfather with the adjustment setting or is it easy enough to calibrate? I've watched a video and it looks quite difficult to do the full calibration.

 

[MashBag]

Stop bothering the yeast they will take offence


https://www.thehomebrewforum.co.uk/threads/good-smell.103814/#post-1250919

 

[Agentgonzo]

It's easy to recalibrate. Pre-calibrated ones aren't perfect - mine are always a little off. You can probably get a fairly accurate OG with a correctly calibrated ispindel, but the FG will never be accurate. Yeast will cling to it and throw the reading off and one brew will be different from the next. So use the shape of the graph to know when fermentation is done, but don't rely on the actual figure - use a hydrometer to measure the FG.

if you want to recalibrate it, it's fairly easy using the sugar solution method. Or take notes over a few brews of what the ispindel reads for the FG (both gravity and tilt angle) and what your hydrometer said. Then use the calibration software to generate a new formula

I also wrote a quick recalibration tool you can use to generate a new formula from a your existing formula and a OG/FG pair.

https://agentgonzo.github.io/ispindel-adjustment-tool/

 

[Danny-CIPA]

It's easy to recalibrate. Pre-calibrated ones aren't perfect - mine are always a little off. You can probably get a fairly accurate OG with a correctly calibrated ispindel, but the FG will never

It's easy to recalibrate. Pre-calibrated ones aren't perfect - mine are always a little off. You can probably get a fairly accurate OG with a correctly calibrated ispindel, but the FG will never be accurate. Yeast will cling to it and throw the reading off and one brew will be different from the next. So use the shape of the graph to know when fermentation is done, but don't rely on the actual figure - use a hydrometer to measure the FG.

if you want to recalibrate it, it's fairly easy using the sugar solution method. Or take notes over a few brews of what the ispindel reads for the FG (both gravity and tilt angle) and what your hydrometer said. Then use the calibration software to generate a new formula

I also wrote a quick recalibration tool you can use to generate a new formula from a your existing formula and a OG/FG pair.

https://agentgonzo.github.io/ispindel-adjustment-tool/

Perfect thanks for the response yeah that makes sense surrounding the FG. I will make sure I take some better readings on my next brew and try your tool to readjust my iSpindle.

As you seem to know about this would you say a refractometer is better than a hydrometer? I currently have a hydrometer and tested it at 20° c with water it was pretty much spot on so just wondering if I should also get a refractometer as a confirmation check or is that just overkill?

 

[Agentgonzo]

If you're happy with your hydrometer, then trust that. The refractometer is overkill.

Refractometers can give you a reading with less wort as you only need a couple of drops, but imo they are less accurate and a little bit harder to use. If taking the FG you need to factor in your OG and apply a formula to get the FG.

 

[Danny-CIPA]

Super thanks for the responses. Much appreciated!

 

[Twostage]

Refractometer's good point is that you only need a drop to get a reading. I wondered why my refractometer and hydrometer readings never matched then I discovered this :-

Wort Correction Factor

So if you can't be bothered to go through that (I couldn't) then they are useful for knowing when fermentation is over (two readings the same) but I'd still use a hydrometer for accuracy.

 

[Twopan]

@Agentgonzo is right. I have calibrated my ISpindel several times using the sugar solution method. The OG is usually right to +/- 0.001 but the FG reading is always far lower than the true hydrometer reading. They are great for monitoring fermentation progress and particularly, checking readings are flat for two or more days, indicating you can bottle. You still need a hydrometer sample to verify OG, and then to tell you true FG once the ISpindel readings are flat. Using an app like Brewspy, you can fix the OG correctly, and can add points to the ISpindel readings, but I will never be consistent.

 

[MashBag]

Refractometers are good for what they are designed for. Sugar or spirit. Fermented stuff isn't it.

What you really need is a pycnometer. Anyone ever used one? ()

 

[Danny-CIPA]

@Agentgonzo is right. I have calibrated my ISpindel several times using the sugar solution method. The OG is usually right to +/- 0.001 but the FG reading is always far lower than the true hydrometer reading. They are great for monitoring fermentation progress and particularly, checking readings are flat for two or more days, indicating you can bottle. You still need a hydrometer sample to verify OG, and then to tell you true FG once the ISpindel readings are flat. Using an app like Brewspy, you can fix the OG correctly, and can add points to the ISpindel readings, but I will never be consistent.

I guess I should really calibrate it myself then. I'm sold on the idea it won't give good readings for FG which is totally fine but I really want my OG to be as close as possible so I can make adjustments to temperature at a specified point from FG. Right now with it being so far off on OG I never really know where I am within fermentation. Thanks for the reply all

 

[JockyBrewer]

I bought an iSpindel that was supposedly calibrated. I stuck it in plain water and it was reading 1.010.

The vendor gave me a new polynomial to put in the config, which works well enough, although it's nowhere near accurate above 1.060, and the device itself is definitely affected by krausen.

So I wouldn't use it to get anything like accurate readings, it's more to understand how the ferment is going.

 

[hoppyscotty]

If you're happy with your hydrometer, then trust that. The refractometer is overkill.

Refractometers can give you a reading with less wort as you only need a couple of drops, but imo they are less accurate and a little bit harder to use. If taking the FG you need to factor in your OG and apply a formula to get the FG.

Not less accurate....just repurposing a device originally intended for a different application. You can correct for it and have as accurate pre fermentation gravity readings as accurate as you need.



By the way the accuracy of cheap hydrometers isn't great. The one I have reads 0.004 high in distilled water.

I would never expect to try to make an iSpindel or any floating hydrometer accurate for gravity readings. They are are incredibly sensitive things so a bit of Krausen still on the lid or it resting on the side will impact its reading so you can never trust the reading no matter how well you calibrate it. Just use it as a rough guide and to track your fermentation trend.

 

[JockyBrewer]

I use my refractometer on brew day, but it's a brix one and I use an app called Refracto to convert it to SG. It nearly perfectly agrees with my hydrometer, so it's very convenient to use.

The hydrometer I use more for during and post ferment readings. Over the years I've found the Stevenson Reeves hydrometers fairly consistent (maybe +/- 0.003 between them), but the Alla hydrometers are dreadful. I bought two from Wilko once and one read 0.004 high and the other 0.004 low!

 

[Agentgonzo]

I bought a cheopo one from Amazon. It's very inaccurate (but in a consistent way). I don't use it that much anymore

 

[RoomWithABrew]

I use the ispindel, a Milwaukee refractometer and it correlates well with hydrometer check reading.
Do use the conversion tool though.
Ispindel always reliable for ferment profile.