Belgian Candi Sugar II

EDIT: I have refined this process somewhat. Please see this this post for some simple changes to my procedure which leads to a better tasting and more consistent candi.

As described a couple of posts ago, I have been working on a method to prepare Belgian Candi Sugar at home.  This method uses commonly available household ingredients to prepare the sugar, and requires no more equipment than you'd normally find in your average kitchen.  I have posted my method in the following video, with this post acting as a synopsis you can follow in the kitchen.

I owe a debt of gratitude to a few bloggers for helping me find my way - in particular, I'd like to direct you to the posts on Ryan's Blog, Life Fermented and on An Engineer & His Carboy for the posts that directed my attempts.  Before I go into the details I'd also like to point out that the method outlined in my video and in this post are the product of about a half-dozen trial runs.  As such they represent a process in development, and may be subject to future improvements.  If you have any luck (or ill-luck) in trying to make your own candi sugar, please let me know in the comments.

EDIT: I have solved some of the crystallization issues people have been reporting when making candi sugar. Details can be found in this blog post.

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The Method:

The method is fairly simple.  I'm not going to cover the science in this post (it is in the video), but in short, we need to mix table sugar (sucrose)  and dry malt extract (DME) to create the mixture of sugar and proteins the we need for the various reactions we are driving.  next, we need to heat to 125-135C (260-275F) to 'invert' the sugar - inversion simply means we break down the complex sugar (sucrose) into the simpler sugars it is comprised of (glucose & fructose).  Next we need to warm the mixture to 135-145C (300-330F) and alkalize (make basic/non-acidic) the mixture to drive maillard reactions - chemical reactions between the simple sugars and the proteins in the DME, which form melanoidins (consistently mis-pronounced by myself as "meladroidins" in the video), forming various flavour and colour compounds.   Lastly, we want to heat the solution one last time, this time to 150-165C (300-330F), in order to develop some caramel and roast flavours, as well as to harden the sugar through developing a hard-crack.

Key Points:

There are a few key points for controlling this process:

1. Food grade lime (pickling/slacking lime) or food-grade lye must be used.  Do not use non-food grade materials.
2. Pre-dissolve the lye/lime into water, and decant off of any solids that remain.  Warning: these solutions are highly caustic
3. DO NOT add acids at any point - they'll slow or stop the flavour development process.
4. The Malliard reactions (135-145C/260-275F) are where fruit flavours form - the longer you carry out this part of the process, the more fruit-like the candi will be.
5. The caramelization reactions (150-165C/300-330F) produce roasted flavours (coffee, chocolate, nuts).  Again, the longer you hold this temperature the more of these flavours will develop.

Lastly, you can stop the process at any point*; stopping after inversion will give you invert sugar (useful for English-style beers), while stopping after the Malliard step will give you a pleasant fruity sugar with minimal roast character.

*I strongly recommend heating briefly to 150C to create a 'hard crack' - i.e. sugar which will take on a hard-candy like product after cooling.  If you do not do this you will get a sticky nougat-like product.  Alternatively, you can add water (~0.5 cups/kg sugar) to make a syrup.

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The Step-By-Step:

1. Measure out the desired amount of table sugar (beet or cane, they are equivalent).  You need approximately 10% more than you want in the end, to cover the losses during preparation
2. For every kilogram (2.2lbs) of sugar, blend in 1 tablespoon (15ml) of DME.
3. Dissolve the DME/sugar mix into heated water - 250ml/1cup per kilogram of sugar.  Heat gently, avoiding boiling, until the sugar is completely dissolved.
4. Once the sugar is dissolved, increase the temperature to 125-135C (260-275F) to begin inversion.  Hold at this temperature or 30 minutes by adding cold water, 1 tablespoon at a time, to the hot sugar mix and stirring.  Try not to over-cool the sugar mix.
5. After the 30 minute inversion period let the temperature increase to 145C (295F), at which point add your food-grade lye or pickling lime, pre-dissolved in water.  Add slowly as to not drop the temperature below 135C (300F).  You will require ~20ml dry lime (pickling lime) or lye (food-grade) per kilogram (2.2lbs) sugar.
• Lime/lye should be pre-dissolved into a minimal volume water and decanted off of any solids
• WARNING: these solutions are highly caustic, so use eye protection.
6. Hold alkalized mixture at 135-145C (300-330F) until the desired colour and flavour formation is complete.  If required, additional lye-lime can be added to drive additional flavour formation.
• Avoid adding excess lime or lye, as minerally flavours can be created.
7. Increase temperature to 150C.  At this point sugar can be cast into a silicone pan or onto a parchment paper.  Alternatively, you can hold at 150-165C/300-330F to produce additional roast flavours.
8. Cast into a silicone pan or parchment-paper lined pan, let cool, and the brew!