Ask the Alchemist #177

Level: Alchemist

Reading time: 13 min

Hi, John – I just watched your roasting video. I am one of those people (for the last 1.5 years since I moved to Seattle) who doesn’t currently have an oven. I hope to move in the next few months, but until then I’ve been taking my beans to my son’s house to roast them in his oven. After watching this video, I’d like your opinion.

The oven is a Wisco – 1300 Watts.

https://www.amazon.com/Wisco-Wisco-620-Commercial-Convection-Counter/dp/B013SF411M

Somehow I made the assumption that using this for my beans wouldn’t be a good idea because the air circulation is so strong inside it; much stronger than a traditional convection oven. When using it for typical baking I need to drop the temp about 25* from what recipes recommend. Now I’m not so sure. This thing is small – about 15in wide, so these are the Pyrex dishes I have that will fit. Of course, I don’t want to take a chance on wrecking a batch of beans. Given what I’ve described, do you see any problem using this for cacao?

 

Let us get this out of the way early.

I am going to lie to you today.

That is a lie.

What I mean by that is that in a binary world, something is either the truth or a lie, and if I am not telling you the whole truth, I therefore must be lying to you.

This is basically I joke I tell to get the attention of a group of 8th graders when I talk about the science of chocolate making.  Go watch my youtube video (https://www.youtube.com/watch?v=fi2RY8zqy9g ) where I tell the whole story.  Suffice it to say, I am NOT going to actually lie to you (on purpose) but I am going to leave a lot out since what I am going to talk about is full of maths and thermodynamics that are going to make many people’s eyes glaze over.  My goal is to get you to understand what is basically going on and why I am making the statements and assertions I make.

truth

And it’s very possible many of you CAN handle the truth.

With that, hold tight, and let’s jump in.

Hard.

First the answer.  Yes, you can use that oven.  For 1 to 2 lbs of beans.

Now I will tell you why I say that.  But I need you to be somewhat conversant in some basic terms and how I think.

From Google – “The British thermal unit (BTU or Btu) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit.”

I am starting there because I know from empirical experience that my Royal #5 coffee roaster produces about 42000 btu/hour with propane.  How do I know that?  I measured the orifice of the propane outlet and looked up the BTU/hour connected to standard liquid propane.

Multiplying that out, that translates to 44310000 joules/hour.

I can roast 35 lbs in my Royal in about 20 minutes or one third of an hour.  That means I need  14770000 joules of energy for 35 lbs regardless of time it takes me to get it there.  Dividing by 35, that means 422000 joules per pound are required.

Part of this kind of number crunching is verifying I am in the ballpark.  I’m going to do that with checking my pre-heat requirements against how long I know it takes me to pre-heat my roaster.

Iron has a specific heat capacity of 0.45 j/g C.

I know my roaster weights about 300 lbs, but estimate the portion I heat up to 350 F is only about one third of it or 100 lbs.

100 lbs = 45 kg iron =45000 grams

350 F is a change in temperature of about 150 C.

0.45 x 45000 x 150 = 3037500 joules to pre-heat.  If I divide by the heat input (44310000 j/hr) and convert to minutes (multiply by 60)

3037500/44310000 * 60 = 4.11

4.1 minutes to pre-heat.  Yep, that is not a lie.  Some days it’s a touch longer, but it’s in the ballpark, so I am counting that as confirmation that my heat input and roasting requirements are about right.

Next, we can use those numbers to see what a 1300 watt convection oven should be able to do.  But we need to get everything in the same unit.

Again, from Google:

“One watt of power converted to joule per second equals to 1.00 J/s. How many joules per second of power are in 1 watt? The answer is: The change of 1 W ( watt ) unit of power measure equals = to 1.00 J/s ( joule per second ) as the equivalent measure for the same power type.”

That just means that 1300 watts = 1300 j/s

We know we need   422000 j/lb.  A little quick math canceling out joules and the minimum time needed in seconds falls out.

422000/1300 = 324.7 seconds.

Dividing by 60 seconds/min tells up how many minutes we need to roast a pound with perfect efficiency.

5.4 minutes per pound.

On the surface, that sounds great.  Except you really don’t want to roast that fast.  If you try, you are going to over roast the outside and under roast the interior.  So you need a slower roast.  No faster than 12 minutes for a roast is what my experience tells me.  But you don’t want to turn the heat down and not use the oven to its capability so that means you should put in more than 1 lb of beans.  How much?  Just divide 12 by the 5.4 minutes for a reasonable estimate.

12/5.4 = 2.22 lbs = 1 kg

Which amazingly enough is right what I said at the top of the article.

“First the answer.  Yes, you can use that oven.  For 1 to 2 lbs of beans.  “

But you will note I said 1-2 lbs.  Why 1 lb?

Well, that delves into modes of heat transfer.  That means when you add heat to a system, there are three ways for it to get from the source to the item you want to heat up.

Convection, conduction and radiation.

This is a convection oven.  That basically means air heating up by the heat source, circulating to the air to what you are roasting and that heat transfers to the cool items (cocoa beans).   It’s pretty efficient since hot air can surround the beans except where it is touch the pan or other beans.  In a thin layer (what I advocate, and why I advocate it) 70-80% of the surface of the bean can be exposed to the hot air.

Conduction happens with contact.  From the surface the beans are on to the beans.  It’s actually pretty inefficient for anything that isn’t perfect flat.  In the case of a cocoa bean, there is probably only 10-20% of the bean touching the surface of the pan.  That is why it doesn’t do well.

Radiation is basically direct line of sight.  When the sun comes out and shines on your skin and you feel warm, that is radiation.  You are not touching the sun and it isn’t because it caused air to move and warm you.  So if there are elements shining on the beans from above, then they are being heated that way too.  If they are heating from the bottom, then very little radiative heating is happening.  Instead the elements are heating the pan and the pan is conducting the heat (per conduction – above) and heating the beans.  In this case, it’s probably the least efficient way to heat.

Ok, deep calming breath.  I know that was a lot.  We are almost done.  And I can now use those terms to talk in a more efficient manner about why you might only be able to roast 1 pound.

Even though this is a convection oven it doesn’t mean it is efficient convection or convection as good as it can be.  Also, conduction is going to be very low due to the very low percentage of bean surface area actually touching the pan.  And where radiative heat might be effective in some cases, the convection in a way circumvents it by distributing the heat around the chamber.  In this case though, that is not a terrible thing and is actually pretty good or the top of the beans might get scorched.

After all is said and done there is probably only 50-60% efficiency going on here.  The rest of the energy is being lost.  Either through the non-insulated walls and glass door or through direct energy loss when you open up the door to stir the beans every 5 minutes or so.  Remember, you still have to stir. If you don’t, the top of the beans will be over roasted and the underside that is in contact with the pan will be under roasted.

And how do I know so much is being lost?  Again experience and puzzle solving.

Years ago I had a drum roaster that I built.  Over time I modified it for efficiency.   It started off at 2000 watts, with a slow 6 rpm motor and no insulation.

If we do the same calculations, recalling we need 422000 joules per pound  and have 2000 watts we find we, in theory, could roast  a pound of beans in 3.5 min.

422000 / 2000 * 60 = 3.5 min/lb.

The drum contained 5.5 lbs of beans.  So if this roaster was working as well as my Royal, I can apply this math:

3.5 (min/lb) x 5.5 (lb) = 19.25 min

And predict it should have taken me a touch over 19 minutes to roast 5.5 lbs of bean.  But the reality of the situation was that I could only roast about 3.5 lbs of beans in that time.  Doing that efficiency check :

3.5 lb / 5.5 lb = 63.6%

This showed me my system was inefficient.   A little over 35%.

It was not until my 6 rpm motor died and I replaced it with a 45 rpm motor did I discover how important REAL convection is.  As soon as I did it, my roast time dropped to 14 minutes. It was like a 35% boost in power.  Efficiency really.   Consequently I was able to add more beans to my roaster.  When I put in 5.5 lbs, my roast time went back to 19-20 minutes – exactly where a good efficient system should be.

See, it was not enough that the beans were tumbling.  Too many were touching and protecting each other from the heat.  Just like in a table top convection oven with beans on a try.  It was not until I got them lofting did real, full convection kick in.  And it is worth noting that after I insulated my roaster, the roast time dropped to about 17 minutes showing again how much heat gets wasted out the walls and over time.  Just like when you open the door to stir.

So, sure, it is a convection oven, but the beans are only partly benefiting from the moving air.  Sure, if it was not convection, then the roast times would go way out to 30 minutes like a classic oven.    But you really can’t have too much convection in a non-tumbling roasting situation.

That is where I get the 50% efficiency count from.  30% or so from non-ideal convection (no loft) and 20% loss from continuously having to open the oven to stir and there you go.

A bunch of lies.  Well, half truths of omission.  And it was STILL a ton of reading.

Yes, you can use that oven.  For 1 to 2 lbs of beans.

And  now , hopefully, you know why and how to work it out yourself if you need.

Go have some chocolate.  You deserve it.

New arrivals

A very limited supply of Belize from Maya Mountain has arrived.

Belize 2016 Organic/Direct Trade:  Smooth, silky chocolate.  The raw beans have an odor of fresh pineapple.  While roasting there is toasted macadamia nuts, warm proofing spelt bread and a lovely savory quality with a touch of tang from fermentation.

The four *new* old favorites from Venezuela are also here. Sur del Lago, Cuyagua, Guaniamo and Canoabo.

                              
                               

Sur del Lago 2016 –   It is a complex, well-rounded cocoa that can make a luscious chocolate bursting with flavor accented by bold red berry fruit, dry cashew, toffee,  malt,  caramel  and most important, chocolate.

Cuyagua 2016 This is what Criollo is all about and what everyone claims to have (but rarely do). It is fruity, delicate, with walnut and plum skin.  The aroma is plum and vanilla, with both coming through in the taste along with a nice back drop of current, vanilla and cream.

Guaniamo 2016 This is a wild harvest Forastero and the most elegant I’ve ever tasted.  Actually, very atypical for a Forastero.  That’s what natural selection can get you.  There is rose and gardenia in the nose.  The flavor is distinctly chocolate with undercurrents of loam and soft leather.   It is rather low in bitterness but has a nice balancing astringency, but not overpowering.  There is distinct acidty, but soft like a malic acid grape nip.  The lasting impression is succulent.

Canoabo 2016.  What it is is a study in balance and elegance. Like a lot of the beans in this region, there is cream and soft red fruits. Red currant comes to mind. There slight tang of mineral molasses for balance. A touch of roasted brazil rounds out the flavor.

Ask the Alchemist #176

Level: Apprentice

Reading time: 10 min

i want to make chocolate peanut butter.  So can i use such grinder I can make in 2 steps namely 1 grind peanuts with cocoa powder and sugar in grinder then for proper and smooth consistency like nutella grind in such stone grinder

nut chocolate

You can use the Spectra 11 to make a variety of things.  Nut butters and their variations are one of them.  Since you can also make praline (hazelnut and sugar) there is no reason you cannot make your peanut butter chocolate creation.  But you may or may not run into some practical considerations.

The main issue you are going to run into is that if your goal is something like Nutella, it may well be too thick for the Melanger.   It is spreadable and does not really flow.  At least if you produce it with the standard Nutella ingredients.

This is one of those times that the use of cocoa powder is called for.  If you are keeping traditional as it were  Nutella consists of the following:

  • 55% sugar
  • 16% Vegetable oil
  • 13% Hazelnut
  • 7.8% Skim milk powder
  • 7.4% Cocoa powder
  • Lecithin

If you do some calculations you will find that it is about 30% fat, which is a touch lower than the recommended 33% fat for most chocolates.  Lower than 33% and your mixture may be too thick to work properly in the Melanger.

But you were asking about peanut butter, not Nutella.  In that case the gloves are off and you no longer have to follow those proportions.  And it is also worth noting that neither peanut butter nor Nutella are actually as smooth as chocolate, which will also work to your advantage.  As will the relatively small amount of cocoa powder the above recipe calls for.

I would recommend first off making sure you are using roasted peanuts.  The same moisture rule applies to nut butters as it does to chocolate.  Too much water will cause the nut butter to get very viscous in the Melanger.  It may flow with it stopped but the sheer makes it push back as it were.  I once almost broke my melanger trying to grind raw almonds.  It wasn’t pretty.

So start with your peanuts.  How much?  I’d start at 60%.  Unlike chocolate that is a solid at room temperature, peanut oil is a liquid so you can avoid having to heat them and the Melanger bowl.  Add them a bit at a time until you have as much as your recipe calls for.  I would suggest giving it probably an hour or two to grind before continuing with your next addition.

That would the sugar.  Even though the Nutella recipe is 55% sugar, I would start off with 25% and see what you think.  Again, I would give that a couple hours to grind down.  You can always add more and keep grinding.

Now you come to a decision.  I said before that cocoa powder would be ok here.  And it would be.  At around 7% you could very possibly just stir it in and be done.  Remember, Nutella isn’t as smooth as chocolate.  Except we are not exactly following the recipe and to make it to 100% total, you are going to need around 15% and past experience has shown me that the melanger is going to have trouble with that.  So, you can either try stirring it in and being done, or, try this upping of the ante.

You have gone through the trouble of using a Melanger and fresh ingredients.  I would suggest going ahead and dropping the cocoa powder and instead use roasted cocoa nibs.  Just put the 15% cocoa nibs (don’t forget to warm them) right into the Melanger.  Since cocoa is about 50%, this gives you the same percent of cocoa in your mix as Nutella but has the advantage of that you will be adding some cocoa butter which will help thicken your mixture (since it sets up at room temperature) without the need for high sugar and other ingredients.  And keep in mind it will be a bit thinner in the Melanger because the cocoa butter is melted.

And after all that, I am going to toss out one more piece of advice that is closer to how I would actually approach this.  At least the first time as I am formulating the exact recipe I want.  Keep in mind I gave you some approximations (60% peanut, 25% sugar,15% cocoa nib) that may or may not be to your tastes both flavor wise and from a consistency/viscosity standpoint.  And at the same time I’ll show you why Nutella has some of that vegetable oil in it.

When I did this I made a batch of sweetened peanut butter and a batch of chocolate and mixed them together (in the kitchen, in bowls, not the melanger) until I hit the flavor proportions I wanted.  For me this was 25% sugar in each.  Then I mixed them in small batches at various proportions until I hit the flavor I wanted.  75% peanut was both too peanut heavy and too thin.  75% chocolate didn’t have enough peanut flavor.  For my tastes 45% peanut butter was just about right but it was too thick.  It was like a chocolate fudge and not spreadable at all.  Enter the vegetable oil.  Or close enough.  Since I already had peanuts in there I added a small amount of peanut oil until the consistency smoothed out to where I wanted it.  In this case it was about 7%.

And a little tip.  When you are testing your proportions, I had the peanut mixture about 60 F and the chocolate at 90F so when mixed, the chocolate set up.  It saved me time waiting for it to cool and solidify.

Once I had my proportions, I was able to make it in the melanger in one go since the cocoa butte kept it fluid while hot but solidified just right when cool.

So there you go.  Three different ways to make a sweetened chocolate nut spread.   See which one works for you and your tastes and go from there.

Ask the Alchemist #175

Level: Alchemist

Reading time: 7 min

So I have the revolution X chocovision tempering machine.

I am noticing at our apartment temperature being an average of 74F our chocolate does not hold nearly as well as others. I have a bar from fruition, rogue, dandelion, etc etc all at about the same 70% ratio and they seem to hold their temper so much better. Some don’t use any cacao butter while others I can tell by texture use quite a bit.

I use these big blobs or “brains” I call them for seeds, I use them over and over but they are all white and flake apart when I put pressure on them… Is it because they aren’t in perfect temper why the resulting chocolate isn’t coming out and holding that glossy black temper for a long time?

I just notice it gets a slight white film on it after a few weeks and the texture gets a tad funky..

Just so you know I am also using the temper 1 setting, so seed out at 90F and molding at 88.7F and then in the fridge to harden.

Should I be using the temper 2 setting where it drops it down and then back up to 88.7? Since the quality of my seed is pretty shit? Just figured I would ask. I am going to experiment as I just read through your illustration of tempering (great job by the way, the best most clear description I have seen yet)

If I just let the chocolate sit at room temperature it comes out really streaky and white 

I figured 74F is just too warm, but based on your illustration it seems the temper might be off?

 

OK, tempering troubleshooting it is today.

For those not sure what is going on here, the method here is a mixture of a way I found works under certain conditions and using a tempering machine with seed.  You can read the whole method here. http://chocolatealchemy.com/illustrated-tempering/

It entails using freshly crystallized chocolate as seed for tempering.  Go read it.  I won’t bore you here repeat it all.

Your issue appears to be that you have combined  methods and are storing and using  old bloomed chocolate instead of the freshly solidified chocolate that I call for.  That is clear, aside from you saying it of course, is because it is white and crumbly.  Forget “not perfect temper”.  These are fully bloomed and devoid of any temper.  Just because you call it seed does not seed it make.

The key to making my method work is that the seed portion that you use must be relatively fresh.  In this state, there is a lot of Type V crystals.  When you put this into your melted chocolate at 90-95 F, all the other types melt and you are left with a substantial quantity of Type V that acts as real seed and you get a good strong temper.

In old bloomed chocolate the amount of Type V has gone down significantly.  As bloomed chocolate ages, there is solid state conversion.  Type V converts to both IV and VI under certain conditions and this most likely is what is causing your issue.  Those blob/brains are your indicator that your have Type VI.  The Type VI melts at even a higher temperature than Type V, so there is no way to get rid of it without destroying your remaining Type V also.

I can’t really speak for your tempering machine’s settings as I don’t know them.  Regardless, going down to 80 and back up won’t fix your issue if you are using Type VI contaminated seed unless you go all the way up to 100 f and then back down, which negates the whole reason for seed.

My recommendation then is to toss your crumbly not-seed chocolate and start fresh.  And after that, instead of using this current method, there is no reason not to just reserve a bar of well tempered chocolate as your new seed.

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I’m not quite sure why spambots have it in for us currently, but we are being hit hard and barely keeping our head above water.  When we don’t keep up, you are going to see the main site lag pretty bad and not load.

We are working on it.

This is just so you know we know.

Thanks.

Ask the Alchemist #174

Level: Apprentice

Reading time: 10 min

I am struggling making my 70% chocolate with only two ingredients.  It seems like what I should do but it is really thick and hard to work with.   It blooms really badly. What am I doing wrong?

Why are you not adding a little cocoa butter?

I mostly keep my head down in social media but I’ve heard through various grapevines that two ingredient chocolate is becoming a *thing*.  And I completely do not understand it.  It is talked about like it is superior or the maker is superior for using only two ingredients.

I guess I am going to soap box here a little, and I don’t mean to offend anyone in particular.  Just take it as my musings on the subject.

It seems maybe this is where you are getting the idea you should be using only two ingredients.  Cocoa beans and sugar I assume.   Trying to suss out why, people toss out phrases extolling the purity of flavor or staying true to the cacao or other such nebulous statements.  At the end of the day, it feels like marketing.  A way to set themselves out from the crowd.  Ok I guess.

If that is what you like, by all means make it.  But I caution the thinking that using only two ingredients is in inherently better.  By what metric?  Sure.  Few people want to eat a chocolate with 27 ingredients where 95% of them are chemical names.  But once you are out of that mindset, I don’t truly get how 2 is better than 3 or 4. Why not 1 ingredient?

But to my way of thinking, it is some kind of pendulum reaction to 27 ingredient chocolate product.  That if that is considered inferior (no real argument there) then the absolute bare minimum must be the best.  This is the same logic that raw chocolate folks make.  Over roasting is bad, so no roasting is best.  That’s bad logic and the world does not work that way.   Too much food (obesity) is bad so no food is best?  Really?  It is the same logic and makes as much sense.  None.

Going back to metrics and why two ingredients are better I would propose these two metrics for consideration.

1)            Adding a little cocoa butter (2-3%) to you chocolate can actually enhance the perceived flavor of the chocolate.   It does this by allowing the chocolate to dissolve faster in your mouth, creating the sense of more flavor.  You are familiar with this phenomenon in regards to sugar.  Which seems sweeter?  Rock candy or granulated sugar?  Both are 100% sugar, but the granulated seems sweeter since it can dissolve faster.

2)            Two ingredient chocolate can be thicker, and more temperamental to temper.  How does this make it better?  It doesn’t.

It is also worth noting that in conversations with supposed two ingredient makers, well over half say they used *a little* cocoa butter in their melangers to make life easier…..which suddenly sounds like 3 ingredient chocolate to me.   This more than anything makes me think they are just playing a marketing game and that it really doesn’t matter.

That all said, let’s see if I can help.

First off, I am going to recommend you reconsider why you want to use only 2 ingredients.  Put aside  what you see other people doing.  Keep in mind that that two ingredient chocolate you tasted and love *may* contain extra cocoa butter.   Evaluate the chocolate you are making for what it is.  Did you actually try making it with a little extra cocoa butter and if so, did you like it better without added cocoa butter?   And why didn’t you make 1 ingredient chocolate if you wanted to *pure* cacao flavor?

Seriously, this is about what you like and enjoy.  And that means the process too.  If you can’t temper it because it is so thick, and it blooms, and you didn’t like the chalky texture, just how did you improve the experience and/or final product by keeping it *pure*?

Ok.  I was going to offer help.  I have heard that people have had difficulty with Tien Giang  being especially thick.  So I roasted 6 lbs and divided it into 3 batches.

1)            The control.  74% cocoa, 26% sugar.

2)            Heated control

3)            20% vodka soak

Spring boarding off my success with the honey chocolate, I mixed in vodka 20% by weight into the roasted nibs.  After soaking in for 2 days, I dried them in an oven for 2 hours at 150F.  To make sure it was not just the heating that made any difference, I also heated an equal amount of roasted nibs the same way.  My hypothesis here was that moisture was causing the extra thickness and that by reducing that moisture, I could reduce the viscosity.

The final results were everything I hoped they would be.

1)            This was thick and very hard to work with.

2)            This was thinner and easier to work with.

3)            This was the thinnest of the three.

The extra drying helped significantly to dry out the nibs, even though they had been previously roasted.  In many cases I think this might be all you need to do if you insist on only 2 ingredients.

The vodka really helped to pull out extra moisture.  I took weight measurements before and after drying  and out of 740 grams of nibs, the heated control lost 5 grams of water, and the vodka treated lost 12 grams.

And the flavors were basically the same.

Alternatively, 3% cocoa butter reduces the viscosity nicely and if you are not allergic, 0.5% lecithin will very nicely bind with the water and make the chocolate easier to work with.  And to my tastes, they all taste just as *pure* and true to the cocoa’s potential.  Your mileage may vary.

If you have not guessed, I lean toward solid data and rigorous evaluation.  Don’t follow a path because everyone else is.  Make what you like and be honest about it and challenge your per-conceived notions.  Maybe they will be right….but maybe you will find there was a heavy placebo effect going on and that 2 ingredient chocolate isn’t anything particular special.

Chocolate you made yourself.  That’s special.

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