Difference in Steam Below and Above 212°F?

Anova Precision® Oven
1

I know you can’t set the oven to sous vide above 212°F, but it seems like there is also a limitation on steam production when set to cook above 212.

For example I created a recipe that was using 200°F with 100% steam, and then transitioning to 350° to finish. When I’d start that cook I’d head two distinct clicks coming from around the water tank at the start, like it was adding water. When finished at 350° the oven would be producing a lot of steam. I wanted to raise the initial steam temperature to around 250°, and still 100% steam. When cooking that way, there were no clicks, and the steam made by the oven was much less.

Is this a correct assessment? The oven doesn’t make as much steam when set to above 212°F?

2

Hi Club, and yes, your assessment is correct, - mostly.

Consider that steam is water in its gaseous state at 212F and at 1 atmosphere of pressure. Steam can’t get hotter than that without increasing the ambient pressure in your cooking vessel.

Your Anova oven is unpressurized, so 212F steam is the hottest you can get. Steam in your oven at 250F would require substantially higher pressure and a Stationary Engineer’s license to operate it. There may be a better explanation in your oven’s operating manual. When I doubt, check your manual or check back here.

When cooking at temperatures above 212F your oven’s steam mode reacts to adjustments in its relative humidity setting. Thus you’re cooking at 250F with 100% relative humidity, not steam.

You’ll soon get the hang of it.

2 Likes
3

No, below 100 C the setting is relative humidity, above 100 C it’s how hard the steam generator works, 0% means it’s off, 100% means it’s working at max power. When we discuss the temperature of steam remember that steam is normally what we call water vapour created by boiling water, water cannot go above 100 C at normal pressure but the steam generated by boiling water can of course be vented into an oven where the temperature is much higher, such as the APO, even if the oven of course is at normal pressure. So, if you’re cooking at temps above 100 C att 100% it just means that the temp in the oven is whatever you set it to and the steam generator is att “full steam ahead”

1 Like
4

It makes more “steam” above 100 C if you set it to 100%, that’s why it´s recommended to steam att 101 C 100% instead of 100C

5

I should have been more clear about water vapor vs. steam.

So, when I run at or below 212°F, it seems like the oven introduces a lot more water. This is revealed by how much water vapor is released during the higher temperature portion of the cook. Why does it seem to introduce much less water with the same 100% when the temperature is set above 212°F? I would have thought it would take more water to hit the same relative humidity at the higher temperature. There’s no water vapor released during the higher temperature 0% steam part of the cook. It seems like the oven is doing something completely different in that case.

6

It is a bit unclear for me, is the high temp part at 0 or 100 % steam? Do you have any food in the oven or are you trying it out?
You should have more steam generated at 100% above 100 C.

Anyway, I just tested 250 F 100%, empty oven, and my APO gets a lot of condensation at the lower right part where the steam escapes, remember you can’t see water vapour only the condensated water, I also see some water droplets running down on the inside of the oven door so there is a possibility that there is something wrong with your oven, have you checked that the water tank is properly seated?

RH above the boiling point is a tricky concept, at best useless or even misleading, you can find Anovas’s explanation why they use power level instead here: Why Steam in a Combi Oven? – Anova Culinary under “How Does Steam Percentage Work?”

1 Like
7

Hi Ragnhild, - No?

Perhaps it’s the relative part of relative humidity that’s a challenge to better understanding. Above 212°F it’s the comparison of the water content in the chamber to the amount of water that heated air can hold or support at the temperature setting, and that’s not much.

This cook is learning a lot from this discussion, but will have great difficulty remembering steam is normally called water vapour. Maybe they should be called, steam and not steam.

And another thing, can it even exist when it’s invisible?

Anyway, this cat frequently sees water vapour, mostly daily when cooking, and then also when it condenses sees it as liquid water too.

It would be useful for Anova or Douglas, our Community’s Resident Engineer, to clarify.

1 Like
8

Reading what you linked to, it says, “At temperatures above 212°F (100°C), the steam percentage you set specifies the amount of steam the oven will generate. In this mode, steam generation is constant and steady throughout the cooking process.” That’s not what I’m observing, though I will try again and watch closely.

Below 212°F, yes. The glass gets condensation, and water vapor eventually starts to escape below the water tank. Above 212 it just seems dry. Maybe a little condensation by the bottom of the glass at the end, but that could have been from the food.

Right now, I’ve just been experimenting with the oven. I’ve owned it since late November, but I’ve had it replaced once already, as the first one arrived with a manufacturing defect (loose screw). I hope this one doesn’t have a problem too. But I do get all the signs of water usage below 212°F. So it doesn’t seem like a physical defect, just a logical one (but I’ve not ruled out the logical defect isn’t in my wetware :wink: ).

Mostly I’ve been reheating pizza, to get an idea how things work, but just ending up confused on this. I wanted to dial in my own recipe, because the one in the app left the pizza too dry, and way too hot. I was trying to get a lower finishing temperature and more starting steam. The app recipe does 100% steam at 450°F for 5 minutes, then stops the steam at the same temp for another 5 minutes. It never reaches 450 during in the first 5 minutes, but gets close by the end. If I do 212°F 100% steam, and tell it to hold for 1 minute after reaching that temp and head for 350°F with no steam for 5 minutes, I get a nice finishing surface temperature and crispness, but a little soggy in the middle. My thought was try to bump up the temperature for 100% steam phase to allow the water to escape the pizza quicker during the crisp phase. But, that also makes a dry pizza, like its doing something completely different, and thus prompted this post.

I’ll try running a simple 100% steam, 250°F, empty oven and observe closely what happens. Do you notice, right after starting with those settings, a click coming from the area in the back of the tank? Then a few seconds later a second similar click? I get that at and below 212. In my mind it sounds like it’s opening a valve to let water into the oven, and then closing it. Above 212°F, I don’t hear that at all. How long did you run your 250°F test? Maybe it doesn’t add water until temperature is reached?

9

Thanks, but I’ll leave it to ANOVA. I have already been told my explanation is too complicated.

10

I work in IT, I like complicated. :slight_smile:

Somewhat related to that one of my earliest jobs was to replace OS/2 on some computers with Windows 95, at a high-pressure steam plant. I was told a story about how when one of their pipes got a leak the room would fill with water vapor, and make finding the source of the leak just about impossible. One, because of the clouds, but also because at the source it was invisible. But it definitely existed. They’d take a straw broom and run it beside the pipe, when it’d come in contact with the super-heated steam the broom would actually catch on fire. Water, setting plant material on fire. :astonished: I’ve been remembering this story while fooling around with the oven. Knowing how much energy can actually be in water when well above its boiling point.

1 Like
11

Sorry for this long answer.

I try my best, being an engineer myself I hope it helps

1 Like
12

Hello! Great question. Above 212F, the steam % is how hard the boiler is working to create steam, and below 212 it is the relative humidity %. And yes, the higher the temp, the lower the overall relative humidity will be. This is just a function of thermodynamics.

1 Like
13

The issue here is certain relative humidity %'s are not possible to reach at higher temps. Like, 350F 100% RH is not possible (in any oven)

1 Like
14

You have it backwards. Below 212F is RH%. Above 212F is how hard boiler works to create steam.

1 Like
15

It’s important to remember steam is invisible. You will not see steam, what you will see (and this can vary with SO many variables such as kitchen temp, etc) is water vapor. “Seeing” steam isn’t a good way to determine if steam is working properly.

16

No, this is simply wrong. You don’ see water vapour, BASTA. What you see are small droplets of condensated water vapour. Steam is water vapour formed by boiling water. Also invisible!
Sorry for being so up front.

17

Yeah, this is getting pedantic, though I do appreciate some good pedantry. We just don’t have a good word in English for “recondenced water droplets suspended in air.” I agree that water that has transitioned from liquid form to gaseous because the energy in it has exceeded the vapor pressure either through evaporation or boiling is water vapor, and invisible. Fortunately my concern here is entirely with steam production, so I can leave the semantics of aerosolized condensation vs. water vapor out of this. :slight_smile:

I am gaining a better understanding how the oven operates at different temperatures now too. And what its targets are with regard to relative humidity and steam production. I’ll be able to run a few trials of different things when I get home this evening.

Thanks everyone for the insight so far!

18

:innocent:

19

Happy cooking! And, yes, lots of good info here!

20

I will mention, only mention, the Mollier Diagram enthalpy - entropy H-S diagram of water states. It might be familiar to brewers here, for use in malting for instance.