[Sca-cooks] Marble slabs

[Tara]

> Actually, in my "dream kitchen", I'd have a 3' x 5' slab (having a 3' deep
> counter).  The slab would be placed above an under the counter
> refrigerator, and the fridge would cool down the slab.  This is commonly
> done in professional kitchens.  It's great for cooling down custards,
> syrups, caramels, pots and rolling doughs that must be kept fairly cool,
> such as brioche or puff pastry.

I'm a little confused about how this works.  Is the slab the actual top
of the refrigerator, i.e. is the top of the refrigerator removed and the
slab inserted as the top insulating body?  If you laid such a slab on
top of a normal refrigerator, it wouldn't stay cool, it would heat up.
A refrigerator is a compressor that pumps heat out of the cavity of the
fridge.  It pours that heat out to the back of the device.  Put your
hand on top of your refrigerator some time - it's warm up there, not
cold.  The compressor is on the back of the refrigerator, which is why
the front and sides don't heat up.  The top heats up because, well, the
heat pouring out of the back of the fridge rises.  The only way you'd be
able to keep the top from heating up would be to forceably ventilate
that heat away from the refrigerator.  But, the top still wouldn't be
cold.  It would be about as cool as any other steel appliance in your
kitchen, just like the sides and front of your fridge.  The insulation
inside the refrigerator is too good to let the outside cool down
noticably.  Otherwise, you'd be refrigerating your whole kitchen, which
isn't very energy efficient.  So, you might as well just put it on top
of a stainless steel countertop.

Of course, if the whole thing is designed so that the slab serves as the
top of the fridge, then that argument is moot.  The refrigerator would
be terribly inefficient, but it would be useful for the things you
mention.  Of course, I would worry about breaking the slab if you're
cooling it that much - the bottom of the slab would be really cold, and
the sudden introduction of a hot pot would be quite shocking.  The slab
would have to be pretty darned thick.

I'm not saying you're lying and that these don't exist!  I just don't
understand how they work...

-Magdalena