SideKIC: Cheap sous vide circulator.

[Duncan Werner]

Sorry for leading you down the wrong path, then. I still think that's what it is, although I have to get somewhere where I can hear that video a bit better. If there's a big difference between the environment and the water temp then it might happen at the surface regardless. I hope it's not too annoying.

[Chris Hennes]

No problem, we're debugging here. If everything worked right the first time I'd be out of a job! Alas, the noise is annoying enough that my wife will almost certainly demand the device be turned off when she gets home. I'll keep experimenting.

[Chris Hennes]

OK, starting from the knowledge that the device didn't make the noise yesterday I started guessing at things that might be different today: first, after long cooking maybe a condensate has built up somewhere in the non-submerged portion of the unit. Second, maybe something in my water has built up on the heater. Third, repeated heat cycling may have moved some internal parts. Fourth, the stars are in a slightly different alignment. Could be cosmic rays, too.

To test the first, I removed the device from the water and blew it dry. I put it back in and... viola. No more noise (so far, it's been two hours). Obviously by blowing warm air through the device I could have affected a number of other things, so this isn't a conclusive source of the problem, but it's a piece of evidence in that direction. Now, we see if the problem comes back tomorrow, and if the same thing fixes it.

[dcarch]

It sounds to me possibly the following:

When you cut Styrofoam, static electricity makes many small pieces sticking every where.

When you put the foam board in the water, the water drains away the static electricity, and small pieces of foam got dislodged and got stuck inside the pump impeller turbine housing and made that noise you heard.

Yes could also be due to the star constellations misalignment.

dcarch

Edited February 10, 2012 by dcarch (log)

[Chris Hennes]

It wasn't the pump (which runs continuously), it was definitely the heater making the noise (which was intermittent). If you've ever listened to the noises a cheap drip coffee maker makes when it starts heating up the water you'll recognize what I was hearing. That doesn't mean that it wasn't foam bits interacting with the heater, however, which may also have gone away when blow dried.

Edited February 10, 2012 by Chris Hennes (log)

[dcarch]

Then you may want to check this out: You will need an volt/ohm meter (Radio Shack, not very expensive).

If there is some electrical leakage inside the housing, which is very possible with inexpensive immersion heaters, and how it is connected to the other components inside, the electric power can start dicomposing the water (electrolysis) and make bubbling noise.

Set the meter at the lowest AC voltage range, with one probe in the water near the unit, and the other probe in the ground hole of the electric outlet. If you measure any voltage then you should not be using the unit at all.

dcarch

[Chris Hennes]

Nope, no voltage, I'm in no danger of electrocuting myself (at least, not from this project ).

[kayb]

A friend coincidentally sent me this today:

http://makeprojects.com/Project/Sous-Vide-Immersion-Cooker/471/1

Being something less than handy, and not possessing some of the requisite tools, I believe I'll stick with ordering a SideKic.

The thread has been fascinating. Thanks, y'all.

[Chris Hennes]

Duncan, is this a bang-bang control for the heater, or proportional?

[Duncan Werner]

Duncan, is this a bang-bang control for the heater, or proportional?

It's proportional.

[Chris Hennes]

The plot thickens... I ask because since I reset it this morning, it appears to be holding a much steadier temperature (perfectly steady, in fact... every time I've spot checked it today it has read exactly 63.0°C, 0.2°C higher than my Thermapen reads and probably within the margin of error). However, when it was making all the noise the temperature was fluctuating much more. So I just turned the temp up a couple degrees, and bang, it started making the noise again. It made the noise for maybe a minute, and then it died down, well before the temp had actually increased enough, so presumably it was still heating even though it was quiet. So this led me to a new hypothesis: what if somehow at some point the device got confused and started behaving more or less like a bang-bang controller, and was throwing full power at the heater whenever it needed any power? When I unplugged it to blow dry it, that reset whatever was wrong, and when I plugged it back in it went back to normal. Maybe the heater only makes that noise when it first starts heating all the way up, but is otherwise silent.

[Duncan Werner]

Well it definitely makes sense that it would be related to power. I said before that I thought it was boiling water on the exposed heater element and I still think that's the case (I could be wrong, but working hypothesis).

[incidentally, there's a small icon on the screen, at the top-left, which shows the power output as a bar graph. It's not precise - the bar graph has 7 levels, while the actual power output is a 16-bit value - but it's a quick way to see what it's doing].

So you have a heat source - the heater - and you have a heat sink, the water. In power terms, a supply and a load. The heater is generating heat and that's being absorbed by the water. In most cases the heat will transfer efficiently - there's so much capacity in the water that all the heat is absorbed, and the heater (including any portion which is exposed) will be the same temperature as the water.

If the water line is low, relative to the heater, then all the heat generated won't be absorbed, and the heater will be hotter relative to the water. If the difference is large enough, just above the water line it will boil the water. Surface tension will pull a small film of water up the heater, to where it's hot, and will boil it.

This is not that unusual - in fact you can make it happen, if the heater is running, by slowly lifting it out until it's less and less in the water (if it's at full power, and about 1/2 of the "coil" is exposed, this will always happen). But ordinarily it shouldn't happen if the heater is submerged, because (1) the heat transfer is efficient, it's designed for that, and (2) again the water should have a pretty large heat capacity, which we're actually increasing by circulating it.

In the ordinary case, you can resolve this by adding more water so that the heater is better submerged. The design is such that as long as the water is above the middle of the bottom window, roughly, it will be sufficient. There may be slight variations, but the top of the bottom window is the ideal point.

Now if the heater is running at 1/2 or 1/4 power, even if it's still slightly exposed, you won't get this effect because there's less power to transfer. In your cooler setup I would guess that you could make this happen by adjusting the set point while it's running - set it to a few degrees above or below the actual water temperature - because it will adjust the heater to either 100% or 0%.

I don't mind telling you that we've been running around today trying to figure out what's happening to you. Generally, we're working on the theory that there's capacitance.

So going back to the power metaphor, we have a supply and a load. We assume that the load is resistive - that is, (loosely), it will absorb power. But if it's capacitive, then it will absorb some amount of power and then stop. At that point, it won't absorb any more power and you get the heat feedback loop I described above.

Why would that be the case? You're using a pretty big cooler, so there's a lot of water which would suggest just the opposite - that water should be able to absorb a lot of heat. However if you were running outside, in freezing weather, then it would be slightly different - the environmental temperature would "hold back" the transfer of heat, (because of the relative heat capacities of water and air). But that's not the case here. If there were a big difference between the environment and the set point that might still happen, but I don't think that's it either, unless your house is extremely cold.

But it could be the cooler. As it happens, my 16 quart cooler just came in so I can do some experimenting. Assume for the moment that the cooler itself is keeping the water cold. Then we try to heat the water, but it won't absorb the heat, and we get some feedback. There's a limit to the cooler's ability, so it doesn't happen when the heater is at 50%, but it does happen at 100%. And then, over time, the cooler's own temperature raises to 63C. At this point it won't resist the heat anymore, so we don't have that effect.

Sorry for the long post. I may know more (for example, I may know that I'm totally off-base) when I get a chance to run my cooler.

[Blues_Cookin]

Great start on the evaluations - I just got back from out of the country today, and will do some work with the SideKIC this weekend. Will let ya'll know if I see anything interesting beyond what Chris has reported on to date.

[Chris Hennes]

Thanks for the post, Duncan (no need to apologize for its length, you are nowhere near the eGullet record ). My update is that there is nothing to report: at the moment the heater has been running for a bit over eight hours since the reset and is completely rock solid at 63.0°C, running in stealth mode with two power bars lit up.

[Chris Hennes]

OK, my first long-time, low-temp cook with the SideKIC has come to a successful close. After that weird initial noise thing it settled into a constant temperature of 63.0°C and held it for 72 hours. The heater stayed at two bars nearly the whole time; when it kicked up to three on occasion there was some noise (of a different sort than before, but probably only different because it was a much lower power setting). The noise issue is going to require more investigation, but since it was dead silent for about 99% of the cooking time after the reset, I managed to stay married, and so far stand by my "buy" recommendation.

[Duncan Werner]

So I'm pretty sure we've figured this out. It's basically what I described above, except for the dodgy part about environmental temperature. Here is what is happening:

(1) As I said above, it's a small amount of water boiling at the top of the heater. This happens when the heater can't transfer heat into the water fast enough. There's some steam generated as well, but this can be hard to see.

(2) Heat transfer is more efficient when the water is at lower temperatures. It's easier to heat up water at 25C than 63C. That's also why it takes longer to heat from 40C - 60C than from 20C - 40C. And it takes longer when there's more water.

So the reason that it was happening is that the water temperature was already pretty high, and you had a lot of water. I'm guessing that that cooler is 16 quarts. When it was trying to heat up to 63C (or maintain that temp) and it had to run full power, heat transfer was less than efficient so there was some residual heat, boiling the water at the top.

When the power level dropped down, it was able to transfer more efficiently - hence no boiling and quieter. We normally don't notice this because while it may happen briefly at high temperatures, it's only temporary while the heater is running at 100%. In your case apparently there was more power required to heat the water (and probably the cooler insulation as well) so it ran making noise for some time.

I can't quite account for why your stopping and starting made it go away - that might have been a coincidence, but we're still tinkering. However while it might be annoying (sorry about that), it's not going to cause problems except for additional evaporation.

One resolution might be to impose a limit on the heater of say 75%, but that would slow down heating so I'd rather not do it if we can avoid it. We will keep investigating.

---

Thanks again for the thorough testing and analysis!

[Chris Hennes]

I can't quite account for why your stopping and starting made it go away - that might have been a coincidence, but we're still tinkering. However while it might be annoying (sorry about that), it's not going to cause problems except for additional evaporation.

Well, it seems that the unit's logic to figure out how much power to apply was messed up: when I reset it and the unit saw that the water temp was perfect it settled itself down nicely, with minimal further noise (but also never having to go above three bars of heating).

When I used the unit again today in a much smaller vessel, again with water preheated mostly, but not completely, it again made significant noise whenever the heater was at three bars or above. I need to try it again starting with room temp water like I did the first time when it was silent, to see if it goes back to being quiet then or if I've done something permanent to it.

One resolution might be to impose a limit on the heater of say 75%, but that would slow down heating so I'd rather not do it if we can avoid it. We will keep investigating.

I really don't think you want to do that: 300W is already a bare minimum, and at 75% output mine still makes plenty of noise at the moment.

[Chris Hennes]

I need to try it again starting with room temp water like I did the first time when it was silent, to see if it goes back to being quiet then or if I've done something permanent to it.

I don't know why I bothered writing this when I could have just gone into the kitchen and done it. Thankfully, when starting from 18°C water back in 5 liters of water, even at full blast it is back to being silent. Which makes sense if the noise is due to boiling water at the heater, I guess, since we're nowhere near boiling. I'm going to bring this batch of water up to 65°C to see what happens.

[Chris Hennes]

Duncan, have you operated the unit much in particularly hard water? I noticed that my heater had gotten a fair amount of mineral build-up on it and I am guessing that it's just from the water.

[Blues_Cookin]

Ok, so far I have made four meals with the SideKIC, along with a couple food-less tests to get a feel for how it can handle pushing up the heat etc. Here are my notes so far:

What I like

• Price point rocks
  
• Water circulation is aggressive - it means you have to occasionally monitor your food bags or secure them to prevent them from blocking the intake, but my temp measurements with my Thermapen in four different positions in the bath all read within 1/10th of a degree C for an hour straight. Impressive!
  
• Software is intuitive and easy to run.
  
• Once at temperature, has no problem holding temp within 1/2 degree C, even with 4 lbs of (dry aged :-) ) steaks in only 9 L of water. This was in a simple rubber maid tub with no insulation and no lid. In a 15 L cooler, also held temp no problem with 2 lbs of sliced potatoes.
  

What I'd like to see considered

• Top Temp of 85 degree C - many starchy veggies need at least 89 C, so if the current 85 C limit is arbitrary, It would be great to see that pushed to maybe 95 C or so. (Can this be done with a software update??)
  
• The corrugated sleeve between the immersion unit and the controller is not very flexible - and is brittle enough to push the controller around. Would be nice if this was a bit more flexible and allowed you to place the controller where I wanted without the corrugated tube trumping my designs.
  
• The heater is not powerful enough to meaningfully HEAT water, though it is very capable of MAINTAINING temp. My tests at 10 qts show that it requires 10 min to gain 6 degrees C at 40 degrees C, but only increases the temp 2.2 degrees C in 10 min at 55 degrees C. You will definitely need to use an alternative source to heat the water bath to close to target temp - I quickly resigned to heating my water on the stove. However, this is not a major issue, I would rather heat the water separately than require a unit that cost twice as much simply because it included a more powerful heater.
  
• On a less important note, the length of the immersion limits the pots you can use. If there was a bit more depth, it would increase the options on the pot.
  
• Beeper when the bath hits the desired temp would be nice.
  

Overall, my initial impression is extremely favorable, especially for the hobby cook. I will certainly be getting a lot of use of my SideKIC, and have already recommended it to a few friends.

Edited February 14, 2012 by Blues_Cookin (log)

[Chris Hennes]

Nice summary, Blues_Cookin, I think we're on the same page. Really, it can't be emphasized enough: the price point is sweet. Period. Yes, you can build the same device yourself for less. Minus the injection-molded plastic container that makes it look like an appliance rather than a science project. The Spouse Acceptance Factor is high with this one.

Have you done any work with it in an insulated container? I really think that with only a 300 watt heater, using an insulated, lidded container is key for the higher-temperature items. You can cook eggs and steak and chicken all day long in a stock pot, but if you want to cook veg, you need some insulation.

[sreeb]

I have an older lab style Polyscience immersion circulator. I think is has a 1200W element. It will readily boil water at the element if it is more than a couple of degrees low. I don't see it as a problem. If it is boiling water near the set point, then the coefficients may need a little tweaking although it may still work fine.

My rock hard SoCal water does leave mineral deposits. I suspect this is directly related to boiling water at the element.

I wouldn't be cooking any eggs in a bath with a circulator. One leaky egg and you will have an amazing mess. The design of the SideKIC looks particularly vulnerable and difficult to clean. If you must, bag the eggs in a ziplock full of water.

[sreeb]

What I'd like to see considered

• 
  flexible and allowed you to place the controller where I wanted without the corrugated tube trumping my designs.
  
• The heater is not powerful enough to meaningfully HEAT water, though it is very capable of MAINTAINING temp. My tests at 10 qts show that it requires 10 min to gain 6 degrees C at 40 degrees C, but only increases the temp 2.2 degrees C in 10 min at 55 degrees C. You will definitely need to use an alternative source to heat the water bath to close to target temp - I quickly resigned to heating my water on the stove. However, this is not a major issue, I would rather heat the water separately than require a unit that cost twice as much simply because it included a more powerful heater.
  

The specific heat of water doesn't change significantly between 40C and 55C. You probably need to either use an insulated tub or lid to reduce evaporation.

I always use hot water from the sink to start (around 130F) to start.

I haven't done any higher temp cooking of vegetables though.

[Chris Hennes]

I cooked both lentils and carrots this evening at high temperature: without insulation or a supplemental heat source the SideKIC's heater had to work pretty hard just to maintain temp. I think that the product was clearly designed with lower-temp cooking of proteins in mind. You can use it for higher-temp sous vide (up to 85°C), but you're going to want to preheat the water and use a well-insulated container or supplemental heat source (a stove on low will do the trick, but also violate their "not for stovetop use" indication in the manual).

[Shalmanese]

I cooked both lentils and carrots this evening at high temperature: without insulation or a supplemental heat source the SideKIC's heater had to work pretty hard just to maintain temp. I think that the product was clearly designed with lower-temp cooking of proteins in mind. You can use it for higher-temp sous vide (up to 85°C), but you're going to want to preheat the water and use a well-insulated container or supplemental heat source (a stove on low will do the trick, but also violate their "not for stovetop use" indication in the manual).

Have you tried using an electric kettle to pour some heated water into the pot and then bailing out some of the old water if it threatens to go above the water line? It's an easy way to add some heat to a beer cooler style setup.