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Melting Chocolate in the Microwave


Fat Guy

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Several pastry chefs, including two on these boards, have cited the microwave oven as the best tool for melting and tempering chocolate. I was wondering if someone could explain exactly how to use the microwave for these applications, and also give a brief description of the purpose of tempering. Thanks!

Steven A. Shaw aka "Fat Guy"
Co-founder, Society for Culinary Arts & Letters, sshaw@egstaff.org
Proud signatory to the eG Ethics code
Director, New Media Studies, International Culinary Center (take my food-blogging course)

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Steven--I melt chocolate in the microwave because it confers two advantages:

First, it removes the possibility of water droplets or water vapor being introduced to the chocolate as it melts, which is a distinct possibility if you use a bain marie.  Very small amounts of water interfere with the structure of chocolate--and can cause it to seize.  (Note I said very small--this explains why a few ounces of another liquid or butter can be melted with chocolate with no adverse effects.)

Second, a microwave provides a constant and quantifiable source of heat.  10 seconds--or any time increment--on high power is always the same--for a given microwave and power rating.  It doesn't change.  Unlike a double boiler or bain marie, which is alot more variable, as you try to guess how much heat is being applied by steam through a stainless steel bowl.  The "heat" being applied to the chocolate mass--in a microwave--goes right through the container--and affects the chocolate directly.

Pastry chefs disagree about the best container to use in the microwave--Jacques Torres, for instance, likes glass or Pyrex, because to him it seems that the glass stays "warmer" longer.  I like using Rubbermaid or plastic because that seems to hold no residual heat at all.  That way, I know a given amount of chocolate is as warm as it's going to be the second I remove it from the microwave and stir.  There's no best way--as long as you understand the differences and adjust the way you work.

Both bain marie and microwave work--and melting large amounts of chocolate in a commercial kitchen is more practical using a big bain marie setup.  And, it's possible to over heat chocolate both ways if you are careless--especially if you try to microwave the chocolate without a turntable and don't stop every 30-45 seconds or so to stir the chocolate with a rubber spatula.

By the way, when I say 30-45 seconds--that's for at least a pound of dark chocolate.  Be much more careful with white and milk chocolate--they are more temperature sensitive.

Also, many pastry chefs who work with chocolate don't use either method--instead, they put big blocks of chocolate in warming cabinets or in their ovens overnight, with just the pilot light on.

(Edited by Steve Klc at 1:19 pm on Oct. 11, 2001)

Steve Klc

Pastry chef-Restaurant Consultant

Oyamel : Zaytinya : Cafe Atlantico : Jaleo

chef@pastryarts.com

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Steve: But melting and tempering are not synonymous, are they? My dim understanding is that tempering involves melting part of the chocolate and then mixing in some of the unmelted until a sort of equilibrium is reached. This I have been told helps with the appearance and/or stability of the chocolate. Can you enlighten us on the purpose of tempering and how it is accomplished in the microwave? As you can tell, I never work with chocolate. Ellen is the baker/pastry-person in the family.

Steven A. Shaw aka "Fat Guy"
Co-founder, Society for Culinary Arts & Letters, sshaw@egstaff.org
Proud signatory to the eG Ethics code
Director, New Media Studies, International Culinary Center (take my food-blogging course)

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Melting and tempering are indeed two separate things, but the vast majority of people will simply need to melt chocolate for use in recipes and baking.  There is no need to temper chocolate for use in ganache, cakes, batters, brownies, creme brulee, etc.  But knowing how to properly melt chocolate is important, especially given the fact that many people are starting to buy and experiment with more expensive and flavorful chocolate varieties.  If you've paid $12 per pound of chocolate, potential miscues can become quite costly.

That's why I responded to your question just by talking about melting--to drive that home first--and not to complicate and or overwhelm by also discussing tempering.  I also didn't mention temperatures--because that also potentially complicates things.  You can overheat chocolate by melting carelessly--but if you use a turntable, and only zap your chocolate with 30-45 second bursts, stirring after each burst, you will not overheat the chocolate.  Just stop when you still have a few lumps--and finish stirring gently until smooth.

Oh, I didn't say this in the first post, but you have to chop up your chocolate first--do not attempt to "melt" a big block or piece of chocolate.  It won't melt evenly and will burn.  And if you are like me--you may want to know what happens when you overheat chocolate?  What happens when you "burn" some chocolate in the microwave?

Well, do it and see.  Put a small amount in a bowl, remove the turntable from your microwave, and zap for 60-75 seconds in place on high power.  The heat will be focused on one area and burn some chocolate to black--while leaving other areas completely unmelted.  When it cools slightly, rub some of that blackish grit in between your fingers--you'll feel sand-like crystals, which results from sugar being fused together, like being burned by a laser focusing intensely in one area.  (Normally the sugar has been ground so finely that it exists imperceptibly in "suspension" with all the other ingredients of chocolate.)  Knowing this up front will help you avoid doing this by accident.  (If it burns, you have to throw it out.)

Tempering is a whole other story--a vast sea of disagreement and mis-information--and if it turns out that our members want to explore this, we can get into it.  You only need to temper if you plan to melt chocolate, use it in pure form while liquid, and then have that melted chocolate reform as a solid--like dipping a ganache truffle ball into melted chocolate.  That chocolate needs to be in temper--because you want it to reform--i.e. solidify--and return to its shiny, hard state at room temperature.  Tempering is the process behind all quality confectionery work--all those dipped and molded chocolates have to be enrobed or dipped or molded in tempered chocolate.  All the solid pieces of plate decoration and showpiece stuff are made with tempered chocolate.

Another way to think of it is this:  when you unwrap a chocolate bar, it is shiny and snaps if you break it.  This is what "temper" means--at room temperature, the cocoa butter crystals are aligned in such a way that when the chocolate cools and solidifies--it returns to this shiny, solid state.

What happens when chocolate is "out of temper?"  Well, it cools eventually, and solidifies, but it never gets completely solid, firm and shiny--instead it is grainy, dull and chalky.  You don't get the snap--because those cocoa butter crystals are out of alignment--this all interacts molecularly, you can't see the particles, those crystals of cocoa butter that have not been melted and aligned properly.

So first lesson--the chocolate you're holding in your hand or shake out of a box or unwrap--is probably in temper to begin with.  One easy way to deal with this chocolate, if you need to convert it to melted, still-in-temper chocolate--is to "directly warm" this chocolate in the microwave by melting it to about 90-92 degrees.

This actually isn't tempering--but rather maintaining temper.  Just melt it gradually, stirring often, and as you get closer--start zapping it less than 30 seconds, going down to say 10 seconds at a time.  All on high power.  Stop way before all your chocolate is melted--still having lumps in your bowl when you are trying to direct warm is a good thing.  Stir gently with a rubber spatula and try to remove these lumps.  If you have done this gradually and carefully--and you have kept the mass of chocolate under 90-92 degrees the whole time, guess what?  Your chocolate is still in temper.

How do you know?  Drag the tip of a paring knife into the chocolate and set it aside--or do what I do, drag a small piece of parchment paper into the chocolate, coating one side thinly and set it aside.  Does that very thin, small amount of chocolate get hard and shiny, without streaks, in a few minutes?  If so, you've successfully maintained temper.  As this bowl of chocolate cools--as anything at room temperature will do--is the chocolate still "in temper?"  Yes--it's just started to drop from 90 to 88 to 85.  If it starts to thicken up, just return it to the microwave and zap for a few seconds, bringing it back up to BUT NOT OVER 90-92 degrees.

What happens if you exceed 92 degrees?  You've blown it--you've broken that invisible proper alignment of melted cocoa butter crystals--and you have to move on to the next step--actual "tempering" rather than "maintaining" the original state of temper in the chocolate.

You only get one shot at "direct warming," but it is the method I use most when I only need a small amount of tempered chocolate--say a few pounds or less.

Steve Klc

Pastry chef-Restaurant Consultant

Oyamel : Zaytinya : Cafe Atlantico : Jaleo

chef@pastryarts.com

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well, you've raised an interesting point and there may be some disagreement with what I am about to say.  Direct warming does not work well with the bain marie--and I do not recommend that you even try.  Microwave it--as I described--or temper it with one of the half dozen or so traditional methods.

It has to do with the fact that the bain marie does not melt the chocolate well enough, evenly enough, initially--and that the heat source and heat transfer over a bain marie cannot be controlled or quantified as well as it can be in a microwave.  Even direct warming in the microwave requires starting with chocolate "pistoles" or chocolate blocks chopped to roughly the same size, so you are more likely to melt it evenly.

The only thing a bain marie is valuable for is to raise the temperature of the chocolate up to 115-120 degrees--which guarantees that all of the cocoa butter crystals have melted out.  Reaching this temperature is the starting point of all the actual tempering methods--at which point the chocolate mixture is cooled down to 80-82 degrees--and then raised to a working temperature of 88-92 degrees.

It is that heating to 116-120, cooling down to 80-82 and then raising to 88-92 that is the real tempering process--which completely melts and then gradually aligns those cocoa butter crystals so that the resulting end product will solidify to something shiny and firm.

How do you know you are at the right temperatures?  I don't recommend you use a thermometer--unless you are prepared to buy an infared laser thermometer, like the one I use.  (JB Prince  800.473.0577) Otherwise, to experiment and play, just rely on your own sense and awareness:  when dark chocolate is at 115-120, lift up some chocolate on your spatula and allow it to drop back into your bowl--it should penetrate the surface easily, in fact, it should burrow and plunge beneath the surface.

When chocolate is 80-82, it begins to resemble fudge.

When chocolate is re-warmed to 88-92, and you do that very same raised spatula test, as it drops off the spatula and falls to the surface--instead of penetrating the surface, the drops of chocolate bead up on the surface and form little mounds of chocolate above the surface.  If you touched a little of this chocolate to your lip--it should feel cool, not warm or cold.  This sense is tough for some to perceive, at first, but once you get it, you get it, and can usually work from visual clues and not need to rely on a thermometer.  

As you start to do this with different couvertures--and you should really temper with "couverture" (a chocolate that has a minimum cocoa butter percentage of 31% which guarantees a certain fluidity) you'll see that they each have their own unique characteristics--some are thicker or thinner and some temper at more or less forgiving temperature points.  You have to figure out what these unique and subtle characteristics are--all of which begins to give you the sense why a chocolatier is such a specialty, such a narrow focus.

This begins to reveal the complexity of chocolate--and expands our discussion of chocolate--because now we're starting to talk about the performance and workability of a chocolate--rather than evaluating differences in the taste of a given chocolate.

Steve Klc

Pastry chef-Restaurant Consultant

Oyamel : Zaytinya : Cafe Atlantico : Jaleo

chef@pastryarts.com

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A pastry chef friend melts chocolate in the microwave in a stainless steel bowl. When I first saw this I ran for cover, but he assured me as long as the bowl was pure stainless steel, there wouldn't be a problem. So now, when I'm strapped for bowls and feeling lazy, I do it too. I know one day the microwave might give out, but there's no denying it works rather nicely -- no sparks, no explosions. You have to be careful to keep the bowl in the middle of the turn table and handle it with care because it heats up quite a bit (but not enough to hurt the chocolate).

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  • 11 years later...

Now I know the purists out there will say that chocolate should be melted in a glass bowl over a saucepan of simmering water, but I have always melted chocolate in a microwave on a low setting.

It does need constant checking and stirring, otherwise too much and the sugar will go solid, but it takes seconds rather than many minutes.

What is the general opinion on this?



http://www.thecriticalcouple.co.uk

Latest blog post - Oh my - someone needs a spell checker

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You definitely should *not* melt chocolate in a glass bowl, IMHO. Glass has a massive capability to hold heat, so if you overheat the chocolate, it's going to stay hot for longer.

My 2c is also that you shouldn't melt it over water, simply because it's so easy to get water in your chocolate. Heaps of people are going to say they've never had problems, but for me, it's not worth the risk. If you use your microwave, with a microwave safe plastic bowl, you're going to have no problems at all, so long as you're careful, monitor the temperature and just use short bursts, never more than 30 seconds. I always microwave on high, just carefully. I've never overheated it.

Other options I have available are a melt tank and a dehydrator set at 45C, dump the chocolate in it and seal the bowl with gladwrap the night before and it's ready to precrystallise the next morning.

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I prefer the microwave, and I melt between 2-20 kgs per day with the nuker.

With the double boiler method, the opportunity to get water into the chocolate is very high. Also, many people make the mistake of simmering the water--when this happens, steam escapes from under the bowl and condenses above the melted chocolate, and you get brown cement....

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I melt chocolate in a 4 or 8 cup pyrex measuring cup. Depending on how much I'm melting I'll start with about a minute on high then either another minute or less depending on how things are coming along. As long as I stick to the Pyrex brand cups I haven't had any burned chocolate - it doesn't seem to get the hot spots of other glass (or stainless) vessels I've used.

White chocolate in small quantities - I'd probably start with 20 seconds.

When I'm trying to warm up chocolate that is already tempered but is getting cool - I usually nuke on high power in 6 to 8 second bursts.

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PSmith, I don't understand your comment about "sugar going solid". Can you elaborate?

On occasions (especially when using budget chocolate - not the 70% stuff) the sugar in the chocolate re-crystalises if you use too high a heat in the microwave.

http://www.thecriticalcouple.co.uk

Latest blog post - Oh my - someone needs a spell checker

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  • 6 years later...

Lately I have been using a combination of microwave and melter, due the fact that I need larger quantities of chocolate, but I don't have a large melter. I do leave an 11 lb block over night in the melter, and then I melt more during the day as I go.

Vanessa

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