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rosenblumr_gw

Rational-a different kind of oven

rosenblumr
15 years ago

When a friend of mine who is a chef heard I was deciding between all sorts of expensive ovens, along with a steam cooker and a speed cooker, he asked me to take a look at this (I will warn you, pretty it is not):

http://www.zesco.com/products.cfm?subCatID=2352&PGroupID=050217AZ02#

(the link is from a reseller not the mfgr--But I highly recommend the videos).

After my friend explains to me how it works, and the price I start laughing. Something about starting at 30K, and having a ched come to my house for 2 days to program it. Then I see the price is 1/3 of what it was a couple of years ago, so I start thinking about it. It gives me everything I wanted from the Miele wall oven, the Gagg wall oven and the Gagg steam oven. Plus it holds more, and cleans more easily and will take up less room than 3 pieces.

I show it to my wife, she laughs, then starts watching the video and laughs some more. Then at the end of the 3 videos I get "I want that."

So I go trying to find out if it can go in a residential kitchen. Seems like it can with some minor modifications. I go for a live demo on Thursday.

Any chefs out there with any experience with this thing.

Taking all opinions, even the sarcastic ones.

Comments (39)

  • alku05
    15 years ago
    last modified: 9 years ago

    I have to say that although I am by a far a function first, aesthetics second person, that thing is pretty ugly.... There's something about the chicken and fish cartoony logos and the 50's space age styling that make me think that I'd be seeing this thing on an episode of Lost in Space.

    If this isn't approved for residential settings, be sure to check your homeowner's insurance to be sure you'd be allowed to install it in your kitchen.

    Let us know how the demo goes!

  • kateskouros
    15 years ago
    last modified: 9 years ago

    will you have another oven as well? or are you going to fire that thing up just for a frozen pizza? maybe a carpenter could make some sort of panel ...never mind, guess not!

  • chefkev
    15 years ago
    last modified: 9 years ago

    I have used these at work and love them. It can cook many things in half the time or less, but the real benefit is total control over moisture and browning. Not only does it have all kinds of pre-set cooking programs you can use for every item, but it also lets you create and store your own programs. You can specify 4 minutes at 90% mositure, then 6 minutes at 50% moisture, then 2 minutes at no moisture. The Miele doesn't let you do that. Want beautiful breads with chewy crusts? Moist duck with crispy skin... I can't afford it now - maybe in a few years!

  • llaatt22
    15 years ago
    last modified: 9 years ago

    You might like something a bit bigger so here's a link. Maybe also a diesel generator to pick up the slack in case 3 phase power is hard to get. Many cruise ships use these units so you might want to see if you can get "close up and personal" on a working vacation/evaluation.

    I'm getting one - when I win a lottery grand prize!

    Here is a link that might be useful: Rational Dream Ovens

  • rhome410
    15 years ago
    last modified: 9 years ago

    Who cares about cosmetics, if it can do all that, I think it sounds beautiful! Maybe it was the warning, but I didn't think it was that bad looking? Kind of an ugly price, though...

  • cpovey
    15 years ago
    last modified: 9 years ago

    As a pro cook, let me temper some of the expectations of the previous posters. Yes, it can hold lots of programs, But remember, restaurants cook the same roast over and over and over and over. Most people don't do this at home.

    Where I work, we order roasts that weight between 17 and 18 pounds and have them delivered daily. Can you get identical roasts every time you want one? No? If not, the program will be off. That's what the programming is for, cooking identical things (generally meats) day after day after day, especially when a chef is not around to monitor things.

    As a long-time computer hardware guy (before I got into cooking for money) I can tell you that three-phase power is, at best, very, very, difficult to get in a home. So without getting three-phase power, you are stuck getting 240 Volt, 70 Amp single-phase power. This is a LOT of power-by comparison, most whole-house AC units are only 50 amps. It is doable, but expensive. You would probably need to up the capacity from the curb to your house, and get a new panel installed in your house. Again, doable-but expensive.

    In short, I thing the unit is not well suited to a home.

    Please, if you really want a combi oven, look at other makers of combi ovens, like Alto-Sham and Henny-Penny, among others.

    Personally, a much better home unit that produces excellent food at a reasonable price is an Alto-Sham AS-250. See link. Note that this is NOT a combi-oven, but a cook and hold oven. Insert a roast or chicken, insert probe into meat, set desired temp and desired cooking temp (generally 200-250 F) and the unit will cook the meat until perfectly done, then hold it at 140 F (minimum safe temp) or whatever temp you specify for hours and hours. Much more practical, IMHO, for home users. Prep a roast at night, throw it in before you leave for work, and it will be perfect when you arrive home, no matter the time. Great at Thanksgiving.

    Here is a link that might be useful: Alto-Shaam 'slow cooker' or cook and hold oven

  • chefkev
    15 years ago
    last modified: 9 years ago

    cpovey - didn't realize the electricity requirements, thanks for pointing it out. I worked at a cooking school and got to experiment with our rational Combi oven. I got pretty good at eyeballing different items and coming up with one time guesses for custom 2-4 step programs for different items like breads, roasts, poultry... As long as I kept a close eye on them I could make mid-stream adjustments.

    I still want something with a controllable steam program at home. Perhaps someone will come out with a lower power requirement/more affordable unit for home. I enjoyed looking at the alto-sham options. I've just about finished my kitchen remodel so we're financially tapped out and won't be getting anything any time soon. Still it's fun to look at the possibilities.

  • FunChef54
    10 years ago
    last modified: 9 years ago

    Hey, just wondering if you went with the rational after all.

    A few things after research. A few months after you posted, rational introduced a new feature that descales the boiler when you put it into the automatic cleaning program (interior cooking cabinet cleaning).

    You mentioned you guys laughed after you heard the price and what it does. This is a typical reaction when you don't know what you are paying for. Another poster mentioned most commercial chefs make the same roast repeatedly therefore not needing all the different programs. Another poster mentioned check with your insurance. you mentioned 2 days of programming. And another poster mentioned keeping a close eye and making steam adjustments.

    These are all typical home cook methods of thinking. This is not what you do with a RATIONAL.

    Ratioanl is a self-cooking oven. They claim to be the worlds only at this. You want to cook with a rational, take everything you know about using cooking appliances and throw it out the window. You don't need it.

    With rational, you use the picto-grams (self-cooking programs). Then you select type of cooking (roast, grill, fried, broiled, etc.). Then you select you desired results (colour, internal temps, etc.) depending on what you are cooking. Then you walk away, forget about it until it buzzes at you indicating it is done. Why would you want to use it any other way? Yes, sounds like a lot of technology and that is what you should expect from Germany.

    If you want to cook at home and the process is part of your entertainment, don't get a rational if watching it in the oven and monitoring it is part of that entertainment.

    The ability to program is great and I think you can do over 100 manual programs. But why would you want to?

    You also mentioned it was ugly??? Besides a lit up display, door handle and large glass, there is not much else to it. It is stainless steel and you can not even see 1 screw from the front (or any other side for that matter). Just wondering, what is so ugly about it? Compared to other domestic appliances, how does this compare? I think it is the best looking of all commercial appliances out there.

    On the subject of residential, this is a commercial cooking appliance meaning chances are, your insurance will not allow it in a residence where people sleep. Some good insurance companies may give you guidelines that may allow you. A gas unit for sure would need to be under a hood that extends 6" on all sides and vented outdoors.

    I saw a comparison to an Alto-Sham. i hope that unit is cheap because a cook and hold can not do anything more than just that. rational replaces 95% of commercial cooking appliances allowing you to shrink the kitchen. the only other thing you need is an open burner which I recommend an induction 2 burner. Now your cooking kitchen is complete if you learn to do everything in a rational.

    I have to say I am jealous. I would love to do plated banqueting for my next Christmas or Thanksgiving gathering.

    Fresh breads would be awesome and with the new unit they just released, they claim they can do fresh pasta and baking as well. I even saw a chef do creme brulé without the water bath (WTF?). i just came from a wedding that didn't know how to do it right (liquid flammable cover too which tastes aweful). They would definitely have benefited from a rational.

    Note, you would probably also need the rational accessories which could add up. It is the only way to get the results they claim.

    Unit requires water supply, electrical and drain for electric models. Smallest unit which you can do a small overnight roast turkey in requires a 35A breaker. When it is connected to potable water, you never need to descale (or clean the interior) as long as you use their cleaning tabs and clean it after ever cooking (approx. $2 per cleaning cost). The unit looks new again after the cleaning.

    Lastly, in a home, the unit might never break for a long time considering it will not be used the amount of hours it is used commercially but everything breaks eventually. Given it would be installed in a residence, find out what service is available near you and if their insurance allows them to repair it in a residence.

    Hope this helps and if you bought one, hope you enjoyed making the rest of us jealous.

  • Russell Rosenblum
    8 years ago

    Probably a day late and a dollar short;) I am the original poster, and stumbled on this when I was considering getting ANOTHER rational oven. So yes, we did buy it. Absolutely LOVE it. Everything cooks faster, AND taste better. And it is unbelievably easy to use.


    the hardest part is re teaching an established chef to try to approach things differently. But my 11 year old can just "hit the egg button" to make fried eggs rather then continue to burn himself on the range.

    I can't recommend it enough.

  • rhome410
    8 years ago
    Did you have any issues with your homeowner's insurance or the warranty not being honored in a residential setting? Those were warnings I got from the restaurant supply when I considered commercial appliances for our house.
  • Russell Rosenblum
    8 years ago
    Nope. Although I did go with the electric version, and still put it inside a stone area, with steel inside the stone. None of which really will matter, as there is nothing to really catch fire. It is all self contained. We use a hood, but that is really just to vent the steam when we open the door.

    I attached a crummy photo.

    But seriously, love the item.
  • Russell Rosenblum
    8 years ago
    One more thing, where I have not had a claim the house was a. New build and Chubb did tour the house before writing the policy so they DID know it was here.
  • wollmanna
    7 years ago

    Russell, Not sure if you are still following this thread but if you are I have a couple questions. I am considering adding a Rational oven in our home. How did you deal with the requirement for a heat resistant 2" drain. Our home (and I think most) has standard ABS pipe and its only rated for 180 degrees? Also is there much heat radiated out the sides and front?

  • KM Lim
    7 years ago

    Russell, Construction of our new house in Connecticut starts in a few months. Working on detail specs of space for (Electric) Rational oven installation. Even though Rational would not support a home installation (i.e. warranty void), I'm ok with that and I may have found someone who has many years of experience and is willing to do so. I also have Chubb. Would appreciate knowing more about your experience with installation and your satisfaction with the Rational. Thank you.

  • wollmanna
    7 years ago

    We did purchase a Rational 61 series gas unit and a rolling stand. We had to jump when we found a great deal on a near new repo unit. We have not installed it yet as we need to move a wall, install an exhaust hood, add a floor drain etc. So we are probably 6+ months away. Will post pics when done.


  • Jsw ben
    6 years ago

    wollmanna do you have any photos of your completed install? I'm looking to install an electric Rational 61 in my house, and trying to work out extraction/ventilation requirements. Presume extraction is essential?

  • wollmanna
    6 years ago
    Jaw Ben, we are not done with the install yet. we ran into to a lot of problems running the ductwork for the steam hood. We had AC ductwork directly over the oven and had to reroute it. We also had to make a custom sink in the side wall next to the oven so it could drain. We didn't want to put floor drains in because that would require tearing out a lot of the existing kitchen. Getting water to the oven is fairly easy with pex. The difficult part is the drain lines and the venting. We are insulating the walls with rock wool and facing them with stainless or tile. We pretty much have a commercial kitchen now with three commercial hoods with make up Air ( 2 type I with Ansell systems and 1 type II for the rational)
    Photo of the almost done install below. Just a little more tile and then a tuneup from the factory tech.
  • wollmanna
    3 years ago

    In and running for 9 months. We are blessed to have this during Covid times. We can cook amazing meals without much effort. Cleaning routines returns the oven to a new looking mirror finish. They really should make a consumer version.

  • wollmanna
    3 years ago

    Looks great. Does the hood vent outside? You will find the Rational pans very useful. We now have quite a selection. Full tray of fried eggs in 2 minutes. Overnight roasting is amazing. We found 10 -12 hours is optimum so same day works. We have done prime rib, New York roast, brisket (we smoked using the Rational smoker accessory) and a goose this Christmas. All overnight with great result. Steamed broccoli at 258 for 7-8 minutes bright green and perfect flavor. It takes a bit of learning but we have found it is usually better to set target temps a few degrees below desired result so a final brown and crisp will still get you desired result. We use a camber account to package extras and can reheat (even from frozen) using combi mode an you target temp i.e. 130f . Steaks look like they were just cooked.
    It’s our most used appliance. Our char-broiler rarely gets turned on now. Even stocks are made in a deep restaurant pans, brown boranes and veggies in pan then add water.
    .We feel very blessed to have one in our home and believe they would have huge market share with a home version given all their technology patents. They would have to add some safety features like a door that locks you out until steam and high heat vents. They could limit features like multi-level cooking on home versions.
    Enjoy, contact me if you have questions.

  • eug99
    3 years ago

    I agree. we were lucky when we ordered the unit and eded up with the icombi Pro. Its been getting a workout since THanksgiving and we have made 5 turkeys. Generally turkeys are just so unforgiving but 100% humidity sure does a great job on getting it moist. We got an entire selection of pans from Rational , Chefs Toys and Amazon. Agreed that the eggs are fantastic in 2 mins while cooking bacon , toast all at the same time. My main complain is on the ultravent plus. It was designed to not require venting as it has multiple filters, diffusers etc and for $5000 . Unfortunately it does not do a good enough job to dissipate all the odors , especially when you're cooking protein. I am definitely getting a vent similar to you with enough CFMs if we do this again. Happy Cooking ! The rational chef for soCal is working on a program for more home installs. I think Steam cooking is gaining in popularity now that Anova has a Precision Oven out in the market.



  • wollmanna
    3 years ago

    With a full hood you can also smoke. Brisket and roasts come out great since humidity is controlled so no stall. The only downside is no smoke ring but that does not affect flavor. Enjoy!

  • wollmanna
    3 years ago

    I couldn’t find a way to edit a post. But I noted that spell check had gone crazy on some of my post. I meant brown bones for stock and a chamber vacuum for packaging leftovers.

  • mikev23
    2 years ago
    last modified: 2 years ago

    @wollmanna / @eug99 how are the noise levels of this oven when used, and during cleaning programs? I wonder how noisy it gets if you leave it cooking, or cleaning overnight.


    I too was looking at the Rational XS but the 2/3 GN seemed to small. It's interesting that the 61 model doesn't look that big either in a home setting.


    Do you guys have anything you don't like about it?

  • eug99
    2 years ago
    last modified: 2 years ago

    mikev23 - pre-heat / cooking / cleaning cycles are not particularly noisy . It is slightly a few db over a regular wolf / hestans convection oven. The noisier parts of the cycle is when you open the door and the ultravent kicks up to extract all the steam / smoke / smell. Also, there is an option to cool down the oven cavity quickly if you're switching cooking programs that require less heat or if you want to start a wash cycle earlier. Now - thats noisy for 10+ minutes as the door is open, the vent is cycling hard and the fan in the oven is spinning. We were set on the Rational XS. During the pre-install , we realized the XS is only slightly larger than a Thermador , Miele, Wolf Steam oven @ 24 or 27" and its great for portioned protein but it could not handle a 24lb Turkey during the holidays and they both still require 240V circuit. Best decision we made was to go with a 61 that can handle the larger load.

    personally i do not care for the UltraVent+ . It cost close to half the oven and its supposed to clear out all the odor / smoke especially when you're roasting large format meats. The sales pitch is that it does not require outside venting. If I had to do this again, I would install a proper overhead vent w/ large enough CFMs w/ vent out. We have triggered the smoke alarms once or twice when grilling meats at > 500F . Less of an issue when dealing with braising etc. Most restaurants / commercial kitchens just have a standard hood above the rational ovens.

    Husband wishes the probe could be disconnected or wireless . Its always a bit fiddly when you have to load the product into a 550F oven and deal with a very hot probe.

    Finally a small cosmetic issue but the LED lights are in the door . When you open the door , you cannot get great visibility into the cavity as the lights are facing outwards. Different from a traditional oven that has a light inside the oven.

    To be fair .. all minor shortcomings . Cooking with a combi oven has been a game changer in the last 10 months. I dont think we can go back to a traditional convection oven and we have a Hestans Range / Oven in the house as well.

    The trick is to have a good installer that knows what they are doing . Our kitchen has hardwood floors and the installer made sure they fabricated large enough a funnel to allow water drainage with no spills on the side. clearly all works better if you're on a tile floor. I did install a moen water sensor on the floor to ensure there are no leaks. $35 gadget - works like a charm . Good luck !



    BTW : I have 3 separate friends who have been using the Anova Precision Oven for 6+ months and its a great option for $600 . Countertop . Only issue is that you have to vent out the steam when switching from steam cooking -> dry roasting to crisp the protein up. Also, a known issue is the water canister may crack but Anova has replaced it promptly and at no cost.

    Pros - Cost / App driven / regular 110V

    Cons - Smaller (at best a single medium size chicken) , manual venting, cant hit 550F++ temps



  • eug99
    2 years ago

    BTW - Just made Foie Gras torchon 2 weeks back for the first time and it came out amazingly well for a novice home cook. I was trying to re-create the amuse bouche that is served at L'Atelier de Joel Robuchon . Foie parfait + Reduced Port Wine and Parmesan Foam. I adapted the recipes from Chefsteps but sticking the vac bag in the rational with low temp cooking was fantastic. Beats having to get out the water bath , etc for a traditional sous vide. @wollmanna - whats the craziest thing you have tried with your combi ?

  • kaseki
    2 years ago

    What an interesting epic story. I have one question for users that wasn't clear from the reports: Do the units still require 3-phase power? If so, I'm surprised that those of you living in residential areas would have access. (Need 3 HV conductors running across the tops of the telephone poles feeding three transformers, or else located near a major highway where such are typically present.)

    If single-phase cooking units are not available, then it may be of interest that 3-phase power can be generated without having a diesel generator. It will require a big three-phase motor and suitable motor start capacitor. The idea is that a 3-phase motor will operate on single phase once started if the load is well under the motor rating. Essentially, the third winding generates the needed phase-shifted voltage relative to each of the two powered terminals. I use such a rig (1.5 HP motor feeding 1/2 HP milling machine motor), but suspect a 70A (really?) per phase cooking rig might require a motor perhaps rated in the 40 HP region. (This could be second hand.) Total power used by motor and cooking unit would not be much higher than the cooking unit, and would be much quieter than a diesel generator.

    The inconvenient part is that the generating motor should be manually started (with momentary switch) when needed, and shut down otherwise. A single-phase motor 3-phase generator is another alternative. Total steel and copper may be less for this approach and you get a better balanced waveform, but the cost would be considerable compared to a second-hand motor. Solid state schemes also exist, but I would expect them to be pretty pricey.

  • eug99
    2 years ago

    We are utilizing single phase power to drive the Rational 61 (6 rack - half pan) . All of their models from their entire line up - XS , 6 / 10 / 20 rack have models that work on 1-phase or 3-phase power. Its really more of the electrical feed you're getting into the premise that dictates the model. Also, the liquid propane / natural gas models all only require 110V but the lifespan of the ovens are reduced because of nature of a combustible element and may require more maintenance long term. Not sure about heat accuracy as I would like to think that Rational would not sacrifice precision between electric vs gas. There's always the belief that gas sources tend to have residual heat and is not as efficient ? Probably questions for Rational. I know the AMP load seems high but its getting more common to have a 50-70Amps to charge an electric car efficiently . Granted older electical panels would need an upgrade. The XS requires much less AMP when compared to a 61 Rational.

  • jctw
    2 years ago

    Hey guys, I can’t be happier to come across this discussion. I’ve been looking and thinking of getting a iCombi xs for home kitchen for over 1.5yr. I still haven’t gotten it yet though but I’m saving up. This is all very encouraging. I have few questions if you don’t mind sharing your opinions.
    1, are there online forums where you go to for sharing home cooking experiences? Troubleshooting discussion etc?
    2, did you buy a new one or used one? And would you suggest a newbie to go for a new in or used one?
    3, how’s your experience with Rational service? Or maybe your iCombi hasn’t had any issues yet due to home usage only instead of commercial usage?
    Thank you so much in advance!!

  • eug99
    2 years ago

    @JCTW -


    1, I have not found any forums around combi oven usage because there has been so few people that have taken the effort to put in a combi oven due to the electrical requirements. Frankly its the same as putting in a Level 2 charger for a Tesla or any other electric car.

    2. We bought new as these ovens can run 24x7 in certain professional kitchen environments. Clearly i would consider a used model if you got an amazing price and if you could validate the condition and # of cycles it has gone through . Electric has a longer lifespan vs gas just due to the nature of how combustible gas works.

    3. We have service from the company that installed it in for us and they have been phenomenal. No issues really after you put it in and follow the cleaning cycles. These machines are meant to run full time in service kitchens.


    My only advise to share is to look at the 61 model that takes a GN 1/2 pan vs the XS that takes a GN 2/3 pan. The price difference is minimal but you cant roast a 20Lb turkey or a 6 bone prime rib in a XS .


    Good luck


  • jctw
    2 years ago

    @eug99 thank you SO much!!!

  • eatmeat888
    10 months ago

    @eug99 who was your installer in socal? who did you buy the oven from?

  • eug99
    10 months ago

    Supplier was Action Sales in Monterrey Park & installer was Superior Service . Superior took delivery of the oven , rack & performed an initial QC at their warehouse location prior to site planning , delivery , install, test and training + rationals own on site training . It was a good approach as the chain of custody remained with superior and there were no issues with regards to warranty / service . Superior was excellent in ensuring electrical / plumbing / drain was all spec’ed , installed prior to oven hook up . To the best of my knowledge; they may the only one that has done residential installs in Southern California

  • eug99
    10 months ago

    Note - You can use webstaurant but the partnership and existing relationship between the Action Sales & Superior Service teams were pre-established and avoided unnecessary coordination or risked any team passing the buck if damaged or DOA issues

  • eatmeat888
    10 months ago

    I just called Superior Service and they said they won't do residential installs. Do you remember who you worked with?

  • eug99
    9 months ago

    @eatmeat888 send me a private message and I'll pass you my contact info to put you in touch with the team @ superior. They are a large company as they service quite a few major restaurant chains across CA / NV but I know they have done a few installs at some celebrity residences & regular joe residences. I tried to send you a message but your houzz profile is not set up to receive them .

  • eatmeat888
    9 months ago

    @eug99, I actually found them. We're moving forward with a icp 6 double stack

  • eug99
    9 months ago


    2x 20+ turkeys in under an hour

  • eug99
    9 months ago

    and a peking duck at home