silicon cover the surface of water

Yukio-sama,
Good thinking! This will be more resilient than the aluminum foil that many people use.
After watching the video, I searched and found "food grade" silicone sheets here: http://www.rubbercal.com/Silicone_FDA.html
Keep up the good work.
Chris

Very smart thanks Yukio

Now searching for the silicone sheets in Europe.

simply brilliant idea! thanks for sharing.

I've never seen this before. How well does it reduce boiling times? Does tinfoil deform?

Clever indeed!

Casey, IIRC a tight pot lid or a layer of oil atop the water yields an energy savings on the order of 30% (by reducing evaporative heat loss).

I'd welcome a more accurate value than that provided by my memory :-)

Than expected, on relief from the heat of the water.
Feathers as well as sleeping bags, air layer is formed by the trap someone.
That, I think the effect is going up.
Multistage able to devise and better.
And, like pan, arms stretched out and
Easy to treat.
Is unsuitable for cooking elaborate.
Large-diameter pot, the effect should be even larger.

You guys are kidding us right???????

Had me going there for awhile Yukio. I can see that big smile on your face =)

Yukio,

I would like to get some of the 0.3mm silicone material you used in this experiment. Can you give me the specification for the type of material you used?

Thank you very much.

Denis Hazlewood

Google 'silicone rubber sheet': there are tons of suppliers on the web.

cheers

Did I read that right? 2 grams? I never really weighed a square of aluminum foil, but I'd imagine about the same weight? Minus the increase in efficiency…hmmm…so maybe if I used something like this, with a Featherfire in a Ti-Tri cone and a Titan kettle…

Brad,
I'm investigating using this stuff. It's got to float, hence the light weight. I don't know if aluminum foil will work. Worth a try to see.

Do you only get on BPL at work?

I had success with a circle cut from a freezer bag. I assume this is safe because the plastic shouldn't get significantly hotter than when boiling water is poured into the bag.

Denis,
Yeah, I'm pretty much on BPL when I'm at work… Does that tell you how much down-time I've had lately? Sometimes on days off, though usually if I'm in project mode or something.

I wasn't originally thinking of floating the Al, but maybe that would work, too. Interesting stuff.

Great Idea!

I currently use a floating Reflectix lid. It is efficient, but the edge is a food trap and it sometimes takes a quirt or two of water to get it clean.

Next consider two or more sheets of thinner silicone bonded at the edges to provide air gaps and more insulation.

Verrry interesting.

This is crazy, and I don't get it. What stops steam from escaping on the sides?

Why is this a better idea than aluminum foil on the top of the pot? Or is it just a different and interesting idea?

Definitely interesting!
Doug

wax paper will work. It can be used as a substitute for a Japanese drop lid, which typically is made from cedar.

Doug,

I think Yukio is adapting or using the idea of a Japanese drop lid. These are common in Japanese cooking for simmering of dishes. They are excellent in that they keep the heat in and allow cooking of delicate ingredients without having them roll around with lots of movement. Items at the top will cook better too. They also have the advantage that you don't get boil over. There is a small amount of steam that will escape out the sides but it is a small amount. Not really sure what effect it would have on boil times though.
http://en.wikipedia.org/wiki/Otoshibuta

Informal test just performed.

Stove: Snow Peak Giga Stove – Stainless GS-100A

Wind Screen: Snow Peak Titanium Bowl (modified)

Pot: BPL Firelite SUL550 (Ti spoke bail installed)

Water: 2 cups from tap. Temp: 53°F. Room Temp: 65°

Timing: Casio quartz stopwatch.

Test No.1: Above rig with aluminum foil disk lying on top of water (no pot lid). Boil time 0:5:37.

Test No.2: Above rig without aluminum foil disk (no pot lid). Boil time 0:06:05.

Test No.3: Above rig without aluminum foil disk (using pot lid). Boil time: 0:05:30.

It looks like I could leave the pot lid at home and just use the aluminum foil disk. Or, as noted on this thread, a disk of polyethylene freezer bag material, which is probably more durable than the foil.

I'll probably just keep using the pot lid. I'm not as likely to lose it.

Edit: If I can locate a source of FDA 0.3mm (0.015") silicone sheet, similar to the type Yukio used, I would probably use it in conjunction with the pot lid. Why be half safe?

If you are looking for silicone sheet you might look at silicone dehydrator sheets for doing fruit leathers.

I found some on eBay that look like they might work and the price is reasonable. I'm not sure if they are pure silicone or a laminate but they say they are good up to 500 F. and presumably food grade.

Just a thought.

-Mark

http://cgi.ebay.com/Dehydrator-Sheets-Flexible-Silicone-for-Sticky-Items_W0QQitemZ250304223494QQcmdZViewItem

I found a quite thin sheet of teflon (superlight cutting board) that might work.

"What stops steam from escaping on the sides?"

Steam is created thru "agressive evaporation" from the exposed surface area of water. With a silicone layer laying flat on the surface of the water, the only surface area exposed is between the edge of the silicon and the side of the pot. With less exposed surface area, the volume of steam generated is less, resulting in less evaporative loss of heat overall. If the silicone layer was elevated above the surface of the water (ie: like a normal pot lid) then steam would occur across the entire surface area of the water.

Think of it this way. If you pour 8 ounces of water onto a 9"x12" baking sheet, and you fill a tall narrow glass with another 8 ounces of water, and you set them both uncovered on your kitchen counter – which will evaporate first? The water in the baking sheet will evaporate much faster, as there is a larger surface area for the water to evaporate. Same principle as boiling the water, the evaporation process just isn't as agressive.

Of course, you have to use water in the above test though. If you do the test with beer, the odds are the beer in the glass will be gone before the beer in the baking sheet. Environmentally conscious all the time, we can't just sit there and let that beer evaporate, can we?

I just got back from Wally World with a piece of silicone –
'Dual Purpose Silicone Baking Mats' – two 9"x13" sheets, about 1 mm thick.

A 4" diameter circle weighs 0.440 ounces versus the 0.090 ounces of my Reflectix floating lid.

So the search continues for that 1/4 mm sheet….

水から水蒸気へ変化するときに必要な熱量はとても大きいです。
一般的な蓋では、水蒸気になるのを阻止することは
ほとんど出来ていません。
すでに出来てしまった水蒸気を、なるべく逃がさない機能だけです
自由に水蒸気は発生し続けています。
燃料の多くを、水蒸気に消費されてしまっています
気が付きにくいですが、真実です。
それはバックパッカーにとって、とても悲しい現実です

落し蓋
水蒸気に変化することを、かなり妨害出来ます。
その結果として、無駄な大量の熱量を使わずに済みます。

１．担ぐ重さを減らせます
２．早く沸きます
３．蓋の重さを、とても軽く出来ます

材質は、シリコンがベストではありません。
耐熱性、軽量、であるものを探しています。
水に浮き易いことも希望しています

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
When you change from water to steam to a very large amount of heat is needed.
In a typical roof, to prevent water vapor will be
Most are not good.
Water vapor has already done as much as possible is the only seal feature
Steam continues to occur freely.
A lot of fuel, water vapor had been consumed.
気GA付KI difficult, but the truth.
For the backpacker, is a very sad reality

OTOSHI-FUTA
To changes in water vapor, a significant interference.
As a result, large amounts of waste can be done without the use of heat.

1. Heavy load to be reduced
2. boil quickly
3. The weight of the lid, can be very lightly

Material that is not the best silicon.
Heat-resistant, lightweight, and is looking for.
Can easily float in water are preferred