Inexpensive/beginner/DIY sous vide setup

[Ted Blockley]

The Proportional output is the P in the PID controller.

For sous-vide, proportional output increases the power to the heater relative to the error (i.e. temperature drop). With an SSR, the heating element can be switched on and off rapidly to simulate less than full power. Smaller time increments are generally better and can be adjusted in the controller set up. The 1 second interval is annoyingly close to an at-rest heart rhythm, but longer and shorter times should be perfectly fine.

This method is inappropriate for a mechanical relay, it will wear out with the constant cycling.

[Anonymous Modernist 7382]

Architeuthis,

While glen is correct about relays in general, tblockley's comments are important.

The SSR in your sous vide isn't like a traditional relay. SS allows for many cycles compared to mechanical relays, this is why they are used. But they can generate a lot of heat. The power rating is only for the SSR with the heat sink and the good ventilation. I've too many stories of people building DIY SV using a 25a and no heat sink. They hook up a 1000w heater and blow out the relay. If your using 1000W or less and have the heat sink and some ventilation, you should be fine.

[Anonymous Modernist 7751]

Thanks guys! I appreciate the answers, they help me understand this stuff a bit more

[Ted Blockley]

Mheadroom brings up a great point. The flat bottom of the SSR is made to transfer lots of heat, but only if properly installed.

Another consideration is (as I've been told by someone very experienced with SSRs) that the usual failure mode is to the ON state. If that happens, there will be a runaway thermal condition in the sous-vide bath itself.

I PIDed my espresso machine after failed pressurestats left molten chunks of heating element in the bottom of the boiler (twice).

Putting some sort of redundant safety in place might prevent an unwanted sous-vide flambé. For example, most espresso machine PID modifications leave the original thermostat/pressurestat intact and in series with the SSR output. That way, if either device trips, the heating element goes cold.

Lacking that, if the PID controller has a relay in it, it is likely that it can be used to cut the heater power if the temperature gets out of range. Check the "alarm function" parts of the PID controller instructions.

[Shel_B]

Could something approximating sous vide be done with a properly sealed bag and a water bath in the oven?

[EnriqueB]

Yes, see http://sousvide.wikia.com/wiki/Give_Sous-vide_a_try_without_buying_expensive_equipment

[Shel_B]

Yes, see http://sousvide.wikia.com/wiki/Give_Sous-vide_a_try_without_buying_expensive_equipment

 

Thanks so much.  The article gives me a starting point.

 

I imagine that temp control wouldn't (couldn't?) be as precise as a dedicated setup, but it might be OK for a few first, rough experiments.  It seems that I have most of the needed items.

[jayt90]

A medium Ziploc freezer bag is fine under 250 F oven temperature.

 

I did 2 lb of haddock fillets and mornay sauce in 2 sealed bags earlier this week. I removed most air with a straw.

They were weighted down in a water bath preheated to 131 F and placed in a convection oven for 1 hour set at 135 F. 

 

The result was good although the sauce thin but nicely flavored.

 

I would do this again for seafood, vegetables, or lighter meats like veal, lamb breast, or chicken.

[btbyrd]

A pot, a thermometer, and an induction burner are the usual tools for improvised SV cooking. Most ovens aren't accurate below 200F and won't be capable of maintaining even heat at the low temperatures required for cooking most proteins. Using a lot of water can help moderate the effects of the oven's temperature swing, but that's only if the thermostat can go as low as you need it to. Salmon, for example, is best cooked between 110F and 120F and I doubt that your oven can go that low (I know mine can't). Temps aren't much higher for tender cuts of red meat... 130F for medium rare. Poultry and pork are a bit higher... between 140 and 145F. Vegetables cook at a much higher temperature (185F) so they might work better. But your best bet is to use a pot on the stovetop. That's how a lot of chefs did it before circulators were widely available.

Edited March 21, 2014 by btbyrd (log)

[gfweb]

For short cooks...like a few hours...a large volume of water heated to temp and poured in a beer cooler will maintain temp nicely. Check out Kenji Alt's "ghetto sous vide" article at eater.com

[dcarch]

"------Most ovens aren't accurate below 200F -----"

 

There are more factors influencing temperature in an oven.

 

This was part of a test I did in my gas oven (non-convection):

 

Temperature set at 200F, two identical containers right next to each other, one with water and one with oil.

 

One hour later, oil measured at 190F and water at 155F.

 

Evaporation can have a big impact.

 

 

dcarch

Edited March 21, 2014 by dcarch (log)

[Shel_B]

A pot, a thermometer, and an induction burner are the usual tools for improvised SV cooking. Most ovens aren't accurate below 200F and won't be capable of maintaining even heat at the low temperatures required for cooking most proteins. Using a lot of water can help moderate the effects of the oven's temperature swing, but that's only if the thermostat can go as low as you need it to. Salmon, for example, is best cooked between 110F and 120F and I doubt that your oven can go that low (I know mine can't). Temps aren't much higher for tender cuts of red meat... 130F for medium rare. Poultry and pork are a bit higher... between 140 and 145F. Vegetables cook at a much higher temperature (185F) so they might work better. But your best bet is to use a pot on the stovetop. That's how a lot of chefs did it before circulators were widely available.

 

Thanks for your comments.  Very helpful.  I don't know how low my oven can go, but I do know that my Breville toaster oven can get down around 120-degrees, and I do have a container that will hold water that can fit inside the oven.  How much water can I minimally use ... the container I have in mind holds but two quarts, less, of course, the amount taken up by the item being cooked.

 

Doing it on the stovetop seems like a lot of work, but the water, because of the quantity, might be able to hold a pretty steady temperature, and I do have a few very heavy, thick pots that should help maintain an even temp.  Does that sound about right for stovetop SV?

[Shel_B]

For short cooks...like a few hours...a large volume of water heated to temp and poured in a beer cooler will maintain temp nicely. Check out Kenji Alt's "ghetto sous vide" article at eater.com

 

Very enticing article ... it has a few advantages compared to the oven or stovetop, and one very great disadvantage: space  I'd have to do some careful planning and measuring to store a beer cooler in my small apartment, but I suspect it is doable. 

 

How large a cooler would be advisable, or, perhaps a better question, how small a cooler can I get by with, assuming for now that fish and chicken would be the most cooked items and for no more than two people.

[dcarch]

"----and one very great disadvantage: space---"

 

Instead of a beer cooler, you can try using one of your pots, and wrap it with many layers of thick towel.

 

dcarch 

[gfweb]

Very enticing article ... it has a few advantages compared to the oven or stovetop, and one very great disadvantage: space  I'd have to do some careful planning and measuring to store a beer cooler in my small apartment, but I suspect it is doable. 

 

How large a cooler would be advisable, or, perhaps a better question, how small a cooler can I get by with, assuming for now that fish and chicken would be the most cooked items and for no more than two people.

Glad you found it, Shel/

Apologies for the wrong website. It was seriouseats not eater.

As you found out.

[rotuts]

I have 4 beer coolers for my SV projects.

 

if you want to do just a few things, this will work fine:

 

http://www.amazon.com/Coleman-9-Quart-Excursion-Cooler-Blue/dp/B000G62SJE/ref=sr_1_9/179-4019521-0817211?s=sporting-goods&ie=UTF8&qid=1395431495&sr=1-9&keywords=cooler+coleman

 

I use this size as my SV 're-heater' rig :  a couple of bags, out of the freezer for dinner.  but I have a PID controller etc

 

this would be all you need for sort SV esp fish.

 

N.B.  the top is not insulated.  either you insulate it w foam from a can or cover the thing w a folded over blanket.

 

its easy to check the water temp after say 30 min and add water to keep it at your desired SV temp.  it will stay at that temp once the food gets there and you take into account the top 'as is' is not insulated.

 

microwave some water in one of those pyrex measuring cups to above your target and add a bit at a time and swish the stuff around and check.

 

easy  peesy.

[Shel_B]

There is some frozen fish in vacuum packages (from TJ's freezer) sitting in my freezer.  Could I just dump a package into some hot water of the appropriate temperature, and cook the fish in the package it came in?  Any need to thaw the fish before cooking?

[Shel_B]

I have 4 beer coolers for my SV projects.

 

if you want to do just a few things, this will work fine:

 

http://www.amazon.com/Coleman-9-Quart-Excursion-Cooler-Blue/dp/B000G62SJE/ref=sr_1_9/179-4019521-0817211?s=sporting-goods&ie=UTF8&qid=1395431495&sr=1-9&keywords=cooler+coleman

 

I use this size as my SV 're-heater' rig : `

 

There's a sporting goods store across the street from my apartment, and I'll have time to take a look at what they have.  I figured out where I could keep a cooler of the size shown in your post.  Thanks!

[Shel_B]

Tonight I did a very quick and almost haphazard SV of a couple of frozen salmon fillets.  5 quarts hot tap water into the Le Creuset.  The pot and the amount of water helped, I'm sure, to keep the temp pretty stable.  Set the burner on the lowest setting to keep the water warm.

 

I mistakenly set the water temp too high.  It hovered around 135-deg F for most all the cooking.  Checking back here, it was suggested to cook at about 15 to 20 degrees lower.  I did learn how easy it is to maintain a fairly constant temp with the setup I used.  Next time, a lower temp.

 

As an experiment, and because I was anxious to get started, I put the fish into the pot without removing it from it's cryovac(?) package.  Not knowing what to look for, I don't know if this was, or was not, a good idea.  I can see the downside is not having any sauce in which to cook the fish, but for me that's not a big deal.  I don't mind plain salmon, sprinkle a little S&P and I'm good to go.

 

I am definitely going to try this again.  The fish almost cooks by itself, there's very little energy spent cooking it, cleanup is a snap, and there's no fish smell in the house, which bothers Toots quite a bit.

 

Thanks to all for your help.  Onward with experimentation!

Edited March 22, 2014 by Shel_B (log)

[pbear]

If you want to pursue stove-top low temp cooking, I'd strongly recommend you get a heat diffuser.  You want the two-layer type, e.g., this one available from Amazon, which dissipates heat, as opposed to the thick single-layer type which merely spreads it out.  With a two-layer heat diffuser, you're creating a stable heat-in, heat-out environment which doesn't depend on retaining heat as does the cooler method.  Also, it's small, cheap and useful for general simmering (which, indeed, is its original purpose).

[Mjx]

Could something approximating sous vide be done with a properly sealed bag and a water bath in the oven?

 

Clarify what you mean by 'approximating sous vide'. 'Sous vide' means under vacuum; how are you planning on sealing this stuff? Are you just talking about extended, low-temp cooking of bagged food in a water bath?

[Shel_B]

Clarify what you mean by 'approximating sous vide'. 'Sous vide' means under vacuum; how are you planning on sealing this stuff? Are you just talking about extended, low-temp cooking of bagged food in a water bath?

 

At first I hadn't thought about the vacuum business, and it's still not clear to me why cooking under vacuum is necessary, but as it happens, I may have a Foodsaver setup around here somewhere, if I didn't give it away some years ago.  I'll certainly see if I still have it.  However, I continue to wonder if it's really necessary, or necessary in all situations.

 

From Modernist Cuisine: "Although sous vide literally means under vacuum in French, the defining feature of the sous vide method is not packaging or vacuum sealing; it is accurate temperature control."

 

Additionally, in this video http://modernistcuisine.com/2012/11/watch-nathans-modernist-cuisine-story-on-nova-sciencenow/ - at 8:56 into the video - you can see Nathan serving Martha Stewart salmon cooked in a Ziploc bag, and from the image I saw, it sure didn't look like there was any vacuum involved.

 

So, what's the story?  Is vacuum necessary?

Edited March 22, 2014 by Shel_B (log)

[gfweb]

Vacuum isn't needed. The point of the foodsaver is to get all the air out of the bag so that the meat is in good contact with the bag...in order to transmit heat efficiently.

You can use zip loc bags and the "displacement method" which is described in the SV references here on eG. That's what I do 95% of the time.

[ChrisZ]

So, what's the story?  Is vacuum necessary?

No.

It's a really common source of confusion.  The real point is the low temperature cooking.  You are cooking the food at the temperature you want it cooked at.  If you want an egg at 63C, cook it at 63C - don't drop it in boiling water at 100C and judge the cooking time.  Likewise, if you want a piece of salmon at 50C, cook it at 50C - don't grill it on a 250C hot plate or put it in a 180C oven and try to get the timing right.  While the bagging has some side benefits, the real point is the precise temperature control.

 

Some people call this approach LTLT cooking - low temperature, long time.  It's more correct but I think they face an uphill battle to replace the term sous vide.

 

The vacuum bags and water bath are simply convenient ways to get precise temperature control - easily to within tenths of a degree.  You don't need to do it this way, and there are less precise ways of cooking food with the same approach.

 

In large commercial kitchens dealing with large quantities, it is easier to use a steam or combi oven than to use vacuum bags and water baths.  High end steam ovens (and combi ovens) are also very accurate, maybe not as accurate as a water bath but still within a few degrees.

 

In a general sense, the vacuum isn't the point of sous vide.  The temperature is.

Edited March 22, 2014 by ChrisZ (log)

[dcarch]

Vacuum (or pressure) has nothing to do with sous vide cooking.

 

it is also a way to accelerate heat conduction to food by circulating hot water, in addition to "accurate temperature control" as quoted "From Modernist Cuisine: "Although sous vide literally means under vacuum in French, the defining feature of the sous vide method is not packaging or vacuum sealing; it is accurate temperature control." 

 

As a matter of fact, after you drew a "vacuum" and sealed the bag, if you measure the pressure inside the bag, you will find that the pressure inside is the same as outside. Unlike in a jar or a can, if you vacuum, there will be much lower pressure inside than outside.

 

In the practice of sous vide cooking, "vacuum" is to "evacuate" as much air as possible because air is a poor heat conductor.

 

BTW, the classic recipe for the Chinese "White Cut Chicken" is very much sous vide without a bag or vacuum.

 

dcarch

 

 

[  posted at the same time as above posters.  :-)  ]

Edited March 22, 2014 by dcarch (log)