Sous Vide: Recipes, Techniques & Equipment (Part 5)

[PaulDWeiss]

Hi - has anyone tried to use a commercial deep-fat fryer as a sous vide bath? 6 liter fryers are available new for under US$200. The temperature granularity of the fryer is coarse, but that shouldn't matter if the unit is plugged into a controller. If there's a thread which has already discussed this, I'd appreciate a pointer; I found a short one which discussed the use of a turkey fryer, but without substantive information. (In particular, the use of it and the objections to that use were theoretical; no one had tried it, as far as I could gather.) Tanx, Paul

[Holly Moore]

Though not for sous vide, at McDonald's we used a fryer at low temperature, with an oil bath, to reheat precooked top rounds to be sliced for the Roast Beef sandwich we were trying to develop. My boss, a liberal arts major, called it a tepidarium. As I remember we ran it at something like 160F.

We also used a smaller version, with water, to reheat packets of frozen sliced beef in gravy for another variation of the roast beef sandwich. This we just called a water bath.

[gfweb]

you'd need a circulator

[PaulDWeiss]

An aquarium bubbler is the standard for on-the-cheap sous vide systems using rice cookers.

[PaulDWeiss]

Though not for sous vide, at McDonald's we used a fryer at low temperature, with an oil bath, to reheat precooked top rounds to be sliced for the Roast Beef sandwich we were trying to develop.  My boss, a liberal arts major, called it a tepidarium. ...

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Sooo, directly from the frigiarium to the tepidarium?

[Holly Moore]

My boss called a frigiarium a walk-in. I think he only had a B.A.

[nickrey]

Hi - has anyone tried to use a commercial deep-fat fryer as a sous vide bath? 6 liter fryers are available new for under US$200. The temperature granularity of the fryer is coarse, but that shouldn't matter if the unit is plugged into a controller. If there's a thread which has already discussed this, I'd appreciate a pointer; I found a short one which discussed the use of a turkey fryer, but without substantive information. (In particular, the use of it and the objections to that use were theoretical; no one had tried it, as far as I could gather.) Tanx, Paul

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The temperature granularity isn't all you'll need to worry about. Of more interest would be the distribution of heat. Rice cookers are ideal as they tend to have been designed to have a more even heat distribution because of the nature of what is being cooked. For high temperature frying, this is not as much of a consideration and hence not part of their design.

There will also likely be more heat loss from the fryer as they are not typically as well insulated as rice cookers, which are made to hold rice as well as cook it. As a consequence, there will be more heating and cooling, meaning that there is a good possibility of heat differential across the item that is being cooked. It will also use more energy because of the requirement for additional heating.

Bottom line, it could most likely be done but you will need:

1. a very good circulator, and

2. to be very careful setting the PiD parameters.

You can get a rice cooker for the same price you have quoted for the deep-fat fryer. It is what a lot of us use for sous vide.

I suppose your decision is how much you want the other use of the appliance (ie. deep-frying or cooking rice) in addition to using it for Sous Vide.

[e_monster]

6 liters is pretty tiny and for a lot less than $200 you can get something that will work every bit as well when plugged into a temperature controller. I often use a 6 quart Presto Multicooker that runs about $35. I have had it for 20 years and it works great for cooking small amounts of food sous vide. With a 6 liter water bath, you can cook a steak or a couple of chicken breasts or a couple of short ribs. You will need something with a much larger capacity to cook things like brisket, roasts and the like.

The multicooker is very responsive when used with a PID temperature controller. When the controller is set correctly, I get no overshoot.

Hi - has anyone tried to use a commercial deep-fat fryer as a sous vide bath? 6 liter fryers are available new for under US$200. The temperature granularity of the fryer is coarse, but that shouldn't matter if the unit is plugged into a controller. If there's a thread which has already discussed this, I'd appreciate a pointer; I found a short one which discussed the use of a turkey fryer, but without substantive information. (In particular, the use of it and the objections to that use were theoretical; no one had tried it, as far as I could gather.) Tanx, Paul

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[RWells]

Hi - has anyone tried to use a commercial deep-fat fryer as a sous vide bath? 6 liter fryers are available new for under US$200. The temperature granularity of the fryer is coarse, but that shouldn't matter if the unit is plugged into a controller. If there's a thread which has already discussed this, I'd appreciate a pointer; I found a short one which discussed the use of a turkey fryer, but without substantive information. (In particular, the use of it and the objections to that use were theoretical; no one had tried it, as far as I could gather.) Tanx, Paul

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The temperature granularity isn't all you'll need to worry about. Of more interest would be the distribution of heat. Rice cookers are ideal as they tend to have been designed to have a more even heat distribution because of the nature of what is being cooked. For high temperature frying, this is not as much of a consideration and hence not part of their design.

There will also likely be more heat loss from the fryer as they are not typically as well insulated as rice cookers, which are made to hold rice as well as cook it. As a consequence, there will be more heating and cooling, meaning that there is a good possibility of heat differential across the item that is being cooked. It will also use more energy because of the requirement for additional heating.

Bottom line, it could most likely be done but you will need:

1. a very good circulator, and

2. to be very careful setting the PiD parameters.

You can get a rice cooker for the same price you have quoted for the deep-fat fryer. It is what a lot of us use for sous vide.

I suppose your decision is how much you want the other use of the appliance (ie. deep-frying or cooking rice) in addition to using it for Sous Vide.

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If it's volume and cost that are your issues try an el cheapo Rival roaster. 18 quart, under $40 and with a ten dollar aquarium circulator I haven't had any problems maintaining a temp with a Sous Vide Magic unit. I've cooked everything from fish to 72 hr Short Ribs.

[RWells]

Hi - has anyone tried to use a commercial deep-fat fryer as a sous vide bath? 6 liter fryers are available new for under US$200. The temperature granularity of the fryer is coarse, but that shouldn't matter if the unit is plugged into a controller. If there's a thread which has already discussed this, I'd appreciate a pointer; I found a short one which discussed the use of a turkey fryer, but without substantive information. (In particular, the use of it and the objections to that use were theoretical; no one had tried it, as far as I could gather.) Tanx, Paul

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If volume and price are significant issues why not use a Roaster. Presto makes a 18 quart model that is always on sale at less than $40. I have never had any problems controlling at standard auto tune PID with a Sous Vide Magic. Cooked everything from salmon to 72 hr. short ribs with total temp control. I use a rice cooker for most short cooks, but when you need to cook for several folks, Presto Roaster and a rib rack (to separate the bags) are hard to beat.

[ChristinaM]

you'd need a circulator

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An aquarium bubbler is the standard for on-the-cheap sous vide systems using rice cookers.

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Interesting.

I've been thinking about fish tanks and sous vide (I really can't afford/justify the expense of a 'proper set up). Apologies if this has been covered earlier in the thread, I did a search but the results weren't helpful! Could I use a small fish tank, aquarium heater and seperate thermostat? Circulation could be easily provided by a small aquarium powerhead. Aquarium heaters are available up to at least 500w and are very efficient and reliable. My husband likes the idea as he reckons he could insulate the whole tank with polystyrene tiles to save energy!

[joesan]

In response to the question about using a deep fryer - yes it can be done and works very well. I've used a Gaggenau Deep fat fryer with a manual switch set to full power. Control with a PID controller and you've got a stable dual purpose machine., with the added benefit of being able to deep fry at very precise temperatures. You can add a circulator but equally you can do without one. I don't know if anyone here has done sufficient testing on circulator/no-circulator setups to determine the degree of variation empirically. I can tell you that I have SVd things (steaks, pork, chicken, game, vegetables etc.) perfectly well without the use of a circulator. You will not get 0.1C accuracy with this setup but consider how nicely most things turn out without even a 10C knowledge of the true temperature when cooked conventionally.

The Fish tank aquarium idea should work but there would be problems raising that mass of water to the correct temperature in a reasonable time with such a small powered heater. Insulating the tank with polystyrene sounds good but will bring about it's own problems such as will it allow the water temperature to come down enough in a reasonable time when the PID goes over the target temperature.

For anyone wanting to DIY this I think the main guidelines are you can use just about anything as a heat source and as a vessel. If you add a PID you'll get there eventually. Circulation adds accuracy but may not be essential if you're trying to keep costs down. If you sous vide something to within +-2C you will still get a very good result for most proteins. Bearing in mind that there are certain minimums below which it may be unsafe.

I think in general you want a largish container, not too much insulation, some agitation of the water, and reasonably powerful heater.

[ChristinaM]

Thanks joesan. I could, of course, use more than one heater, one of the reasons I thought of them is that they are very responsive. I'm thinking of a small tank, maybe 18"x12"x12", how much water should I use in terms of gallons (or litres)? I am now going to look at an aquarium thermostat and see how high it goes....

The other bonus is that all aquarium eqipment is food-grade.

Edited March 25, 2009 by ChristinaM (log)

[adey73]

I've found that waterbaths upto 12 litres are temperature stable, with not much variation or cold spots. Above that you probably need a pump for circulation.

Edited March 25, 2009 by adey73 (log)

[joesan]

Christina - I don't know what your budget is but if you are in the UK you can buy a PID contoller for about £30 from eBay, with some basic electrical knowledge you can interface just about any heat source to it.

I normally use about 6-10 litres of water but have used as little as 3 litres. In general a larger amount of water will remain more stable but will, of course, take longer to come up to temperature. You can get over this to an extent by heating the water somewhere else, kettle or pot, and mixing with cold water to the appropriate approximate temperature.

[ChristinaM]

Thanks adey73 and joesan. Any excuse to get myself back onto ebay! The kettle idea is a good one, I've been known to do that to do an emergency water change in one of the (with actual fish) aquaria.

[e_monster]

I don't think that aquarium heaters will work well for sous-vide -- when I was trying to figure out how to do it on a budget I looked into it and couldn't find a way to make it work. Maybe I missed something -- like a particular brand of heater that would work for this application -- but I did a fair amount of research and came away with the sense that there wasn't workable solution with aquarium heaters.

I would be happy to be corrected with someone that had better luck. Below is what I found when I looked into it.

Most aquarium heaters have thermostats with a fairly narrow range--none of the ones that I looked at could handle temps in the range sous-vide requires. They aren't designed to run for long periods of time outside of the temperature range they were designed for. Cheap aquarium heaters tend to burn out somewhat quickly when used outside of their intended temperature range.

They take a long-time to bring water from room temperature up to temp -- or to recover from the temperature loss when you put in cold food.

Also, the thermostats suffer from the same problem that cheap thermostats all suffer from -- i.e. not as stable as you would like for sous-vide. If the water is already to temperature, they seem stable in normal use because they only need to make up for the heat lost due to radiation. However, if they have to make up for a sudden drop in temperature they don't work so well.

If you want to try sous-vide on the cheap without investing much, I would recommend starting with things that only take an hour or two and using a large pot of water on a really low flame (once the water is at temp) with a good thermometer. Before I invested in my PID, we did that a few times to cook steak and chicken breasts and got results good enough that investing $125 for a PID and table top roaster seemed like a worthwhile expense.

Thanks joesan. I could, of course, use more than one heater, one of the reasons I thought of them is that they are very responsive. I'm thinking of a small tank, maybe 18"x12"x12", how much water should I use in terms of gallons (or litres)? I am now going to look at an aquarium thermostat and see how high it goes....

The other bonus is that all aquarium eqipment is food-grade.

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[joesan]

e_monster - I'm presuming that the thermostat would be overriden, or not applicable, and that a PID would be used. After that you're just left with a relatively low power heating element. Heat is heat so there's no reason why it shouldn't work - eventually...

Personally I don't think it would be ideal but if Christina wants to use what she already has I think it could be made to work. I've made a number of contraptions that all more or less worked as expected. A good easy one is a PID plus Deep Fryer (Cost about £60 in total via eBay) or PID plus Rice Maker (about the same).

[e_monster]

joesan, even with a PID, I don't believe that aquarium heaters are a good fit. They are not designed to recover from large temperature drops and aren't designed to run at temps much beyond 90 degrees fahrenheit.

If Christina already has them on hand and doesn't mind burning them out, it might be worth a try.

If she were going to be buying an aquarium and heaters and PID that would be more expensive than getting a PID and something like a Deep Fryer or Table Top Roaster (which is the most cost-effective unit that I have found for heating 18 litres of water--they are less than $40) or a Presto multicooker ($25) like I keep mentioning. And not only would it be more expensive, I am not even sure that it would work -- none of the aquarium heaters that I looked at had defeatable thermostats and they are likely to burn out fairly soon (compared to something designed to to heat water beyond 90 degrees fahrenheit).

The expense is the PID (roughly $100) -- the equipment for providing the heat is only $40 or less.

e_monster - I'm presuming that the thermostat would be overriden, or not applicable, and that a PID would be used. After that you're just left with a relatively low power heating element. Heat is heat so there's no reason why it shouldn't work - eventually...

Personally I don't think it would be ideal but if Christina wants to use what she already has I think it could be made to work. I've made a number of contraptions that all more or less worked as expected. A good easy one is a PID plus Deep Fryer (Cost about £60 in total via eBay) or PID plus Rice Maker (about the same).

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[joesan]

That's more or less the points I was making - other options would be better but if she already has the heaters they could be made to work, not brilliantly, but work. So we agree...

Pretty good PIDs can be found on eBay UK for about £30. I'm using 4 of them they're great...

Edited March 25, 2009 by joesan (log)

[ChristinaM]

That's exactly it, I have rather a large number of old aquarium heaters, most of them without thermostats of their own. OH has always taken the view that aquarium heaters are much safer and more reliable if controlled by an external thermostat and so far he's been proved right! A pair of 500wt will heat 6 gallons to about 90F in 15-20 minutes. I shall have to experiment...If not I'll try the deep fryer next.

[slkinsey]

Keep in mind that, if a device (e.g., an aquarium heater) includes a thermostat, just plugging it in to a PID will not be enough to override the thermostat. You have to actually remove the built in thermostat.

Another way of putting it is that the PID won't work unless the thermostat of the device being controlled is either removed or set to a temperature higher than the set-point on the PID.

So, if you have an aquarium heater designed to cut off at 90F, and you hook it up to a PID with a 130F set-point. . . I have some bad news: That water bath ain't getting any higher than 90F.

[joesan]

The answers in the post - "That's exactly it, I have rather a large number of old aquarium heaters, most of them without thermostats of their own".

[tomdarch]

Sooo, directly from the frigiarium to the tepidarium? 

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But the whole point to sous vide/low temp is to both avoid the Caldarium and the Vomitorium!

(I know I'm mis-using "Vomitorium" (it's the break in the grandstands through which the gladiators/footballers run onto the field) but I couldn't resist a little really bad architecture humor.)

On the point of the fish tank system: as long as you are pre-heating the water that's going into the tank, why not pre-heat the food on the stove also to avoid stressing the heaters when cold bags go in? I'm thinking that if you're doing a long cook, then warming the food/bags in a pot on the stove a few degrees below the target temp would take care of most of the temperature drop when they go into the tank. Also, if the system is having problems with overshoot, you could easily remove some of the insulation from the sides of the tank. (Besides, the best part of using a tank would be that you could see and photograph the bags hanging in the water surrounded by bubbles!)

Personally, I just bought a new probe thermometer to try some veggies on the stove top. Chadzilla has some interesting posts on potatoes cooked in the 83C range for 40min to 2h. I think I can handle babysitting a pot for an hour or so! He's saying that at 83C, the starch breaks down, but you still have some crispness from the pectins.

I'm going to cube up some Yukon Golds (dunno - 1/2" cubes?) and I'm thinking of olive oil+salt+pepper to start. Anyone have any other veggie suggestions?

[joesan]

Tom - 83c seems to be the magic number for vegetables. I tried some squash using the method outlined in Alinea. I was hoping to find a better way to cook squash than my time consuming grilling method. It looked great but I must confess I was a little disappointed with the texture and taste. It was more or less the way you describe, cooked but crunchy. I can't honestly say the method produced a better result but it was definitely worth trying.