amount of water used in steam ?

It depends on how you are creating it. There was a method described here not too long a go that used a loaf pan and several water-soaked towels.That works really well-I have used it often.

 Or just throw 1/4 c in the bottom of a preheated oven-but NOT if you have an oven glass door! Many members here have described how it cracked the glass!!! Some baking stones dislike cold water being thrown on them and shatter, also.Or glass loaf pans.

(I rarely use a steam pan).

Easiest way is to fill  baking dish 1/2 way with water and put on lowest rack of oven BEFORE preheating.  When loaves are put in the oven it is already filled with steam.  After the bread has baked for 10 minutes remove the baking dish.

I typically just use a long, wide (metal) pan and fill it about half way with warm water. I've found that putting in cold water just takes that much longer for it to get hot enough to create steam. I also use a misting spray bottle.

One thing I tried recently, although its a bit nerve-racking is after you've got the steam going in the oven and the loaves are in, to remove the pan after about 7 minutes. This makes me nervous as I don't like the idea of trying to pull out a pan of boiling hot water with it sloshing all around. Its a recipe for getting very badly burned if you lose your grip. So instead, I just cut back on the amount of water I put in the pan. That way the pan is very close to being empty when I do remove it.

I also tried using one of these steamer devices you might see advertised on tv. However, I found that to be incredibly ineffective as it really lacked the pressure needed to get much steam into the oven.

I don't think there's really any single "magic" method of creating steam. Just find what works best for your situation.

I have found there are "residential" ovens now available that have steam injection built in, but they run in the neighborhood of about $2,500. Ouch!

I keep a cheap metal pan on the bottom rack in the oven.  After the oven has preheated and I'm ready to load in the dough, I put 1/2 cup of (nearly) boiling water into the pan.  In my oven, that amount of water lasts 15 minutes before completely evaporating, so I don't have to worry about removing any extra water.

How much water to use for steam depends greatly on

• which steam generation method you're using
• how quickly steam is "cleared" from the oven out the vent pipe (can be very quick for a convection oven with its fan)

Quantities I've seen vary from 1/4 cup (or occasionally even less) to 2 cups (or occasionally even more).

Open the oven door 7-8 minutes into the bake and see if there's still a little water in your steam generation kludge. If not, use more water next time.

Spray mist is one of the premier ways of generating steam. Like everything else, it does have some drawbacks though:

• if your oven has a light, do not spray mist anywhere remotely close to the light bulb, as it will almost certainly shatter if it gets sprayed
• if your oven door has a glass window in it, get a spray bottle that doesn't drip, and even so cover the glass with a towel while misting (no spray bottle is perfect, and just one drop can crack an oven window)
• as the oven door generally has to be open while you're spray misting, your oven can lose a lot of heat (in the worst case it won't get back up to temperature until the bake is almost over)

I've done my steaming three ways for baguettes with a 67% hydration

1) This guy's method with lava rocks in a pan, using a baking stone preheated in oven and sliding the loaves onto it.

2) Covering the loaves with an aluminum roasting pan before putting them into oven (no baking stone) with the loaves having risen on a cookie sheet with parchment and covered with towel.  I've recently changed to a sheet metal pan to cover the loaves with. Removing the pan after 30 minutes (at 450') and giving loaves an additional 20 minutes.

3) Doing exactly the same but  using a hand held steamer to introduce steam through a little hole in the aluminum as soon as loaves are in the oven.

Results?  Number 2 is the definite winner. Great rise in oven, great crispy crust.