DIY Candi Syrup

There is a lot of misinformation on the internet about candi syrup, what it is, and how it's made. After making 100 or so batches of candi syrup, and hundreds of hours of work and research, I have some insight on this.

First, let's start with what it is. "Candi syrup" or "Kandijsiroop" or "sirop de candi" is dark, richly flavored syrup made from sugar utilizing Maillard reactions and caramelization. In Belgium, tariffs and subsidies make beet sugar much cheaper than cane sugar, so the "authentic" Belgian syrups use beet sugar. There is nothing particularly good about beet sugar. It's just what they use because it's cheap and convenient. The sugar refining process removes any impurities, leaving only the pure sucrose. Beet sucrose is chemically identical to sugar cane sucrose.

Maillard reactions are a complicated set of interactions between a nitrogen source and reducing sugars. Examples of reducing sugars are glucose and fructose. Sucrose is not a reducing sugar, therefore it is impossible for Maillard reactions to occur with sucrose. It is impossible to have Maillard reactions with pure beet or cane sugar in its natural state. To allow the Maillard reactions to occur, one must invert the sugar from sucrose to glucose and fructose.

Sugar can be inverted by heat or acid, or both. The rate of chemical reactions increases with temperature. While it may take several days for acid to invert sucrose at room temperature, it can happen in 30min if boiling. Once the sugar has been inverted, the sugars have become reducing sugars, which can form Maillard products. Any remaining acidity must be neutralized with a base of some kind.

All the manufacturers of candi syrup that I'm aware of claim their product contains only sugar, and is made by repeated heating and cooling alone. This is unlikely to be true based upon the chemistry involved.

The misinformation over candi syrup is caused by two factors. The first is that recipes cannot be patented. The only way to keep your secret recipe from being stolen is to keep it, well, a secret. The other factor is FDA regulations on food labeling. "Process aids" do not have to be included on ingredient labels. "Process aids" are defined as "Substances that are added to a food for their technical or functional effect in the processing but are present in the finished food at insignificant levels and do not have any technical or functional effect in that food." Candi syrup manufacturers are not required to disclose which acids and bases they use in producing their syrups, and to disclose them would mean anyone could reverse engineer their product.

The FDA has guidelines on what products can be used in the production of caramel. Acceptable food-grade carbohydrates:
dextrose (glucose)
malt syrup
starch hydrolysates

Acceptable acids:
acetic acid
citric acid
phosphoric acid
sulfuric acid
sulfurous acid
(In the UK hydrochloric acid is also used)

Acceptable bases:
Ammonium hydroxide
Calcium hydroxide
Potassium hydroxide
Sodium hydroxide

Acceptable salts include any combination of the following:
Ammonium, sodium, or potassium carbonate, bicarbonate, phosphate, sulfate and sulfite.

Lyle's Golden Syrup is a type of invert syrup made with hydrochloric acid and sodium hydroxide. The acid leaves chloride ions, and the base leaves sodium ions. Together they form sodium chloride, or common salt, in the final product.

Knowing accepted ingredients and a little bit about chemistry, we can make an educated guess into the true nature of candi syrup. I have no doubt the product begins as sucrose. Some acid and heat is added until the sucrose inverts. Any residual acid needs to be neutralized. Ammonium hydroxide (NH4OH) would both neutralize any residual acidity and provide a source of nitrogen for the Maillard reaction. If an alternative base is used, some other sort of nitrogen would be needed. Phosphates increase the rate of Maillard reactions, so an ammonium-phosphate salt would have the dual purpose of providing nitrogen and phosphate.

With this information, it is not difficult to devise a substitute for candi syrup. Here is a recipe I've come up with:

3oz Dextrose (corn sugar)
13oz Sucrose (table sugar)
1c H2O
1/2tsp diammonium-phosphate
1/2tsp potassium bicarbonate
1/2tsp lemon juice

1) Bring water and sugars to a boil
2) add 1/2tsp lemon juice
3) simmer for 30min between boiling and boiling+10*F (212*F-222*F at sea level)
Add water as necessary to keep temperature in correct range
4)Add 1/2tsp DAP
Add 1/2tsp KHCO3
Stir well to dissolve

5) Heat to 320*
Add 1/2c H2O
Stir well (be careful as sugar will sputter)

6) Heat to 310*
Add 1c H2O
Stir well
Pour in mason jar or other heat-tempered glass jar, or allow to cool and store in plastic

The reason I include a portion of dextrose (glucose) is that I've found dextrose will darken at lower temperatures than fructose, so having more dextrose will result in a roastier, darker syrup, while more fructose will result in a fruitier, lighter-colored syrup.

Another tweak you can make is heating the syrup to lower temperatures (you can get some nice vanilla flavors around 260*). You can also experiment with the number of heating/cooling cycles.

I encourage lots of experimentation to find what works for you. Maillard reactions are responsible for some amazing flavors, but also foul, acrid flavors. Finding the proper balance between the good and bad flavors is the hardest part of making your own candi syrup.


  1. Hey Nate,

    I really enjoyed skimming through your blog posts. Google landed me here, because I was looking for good candi syrup recipe for my strong dark belgian brew. Yours seems to be very convincing, but there are few things I don't understand.

    Having metric mind, tsp is something that I will never understand, but I get over this issue. How did you come to the result that 1/2 tsp lemon juice can be neutralized with 1/2 tsp KHCO3? Did you measure pH?

    Since I have no DAP available, I'd use ammonium hydroxide. How would the recipe look in this case?

    sugars, water, 1/2 tsp NH4OH and 1/2 tsp lemon juice?


    1. Gyuri,

      Thanks for reading. The good news is, in candi syrup making, you don't have to be exact to make good syrup, and the syrup doesn't have to taste good by itself to make beer that tastes good. So don't worry too much about being exact.

      After I wrote this, I was able to find some ammonium hydroxide. Some conversion factors for you:
      Calcium carbonate - 1 tsp equals 2.6 grams
      Diammonium phosphate - 1 tsp equals 4.9 grams

      I've used ammonium hydroxide a couple times since I wrong this post, and I'd guess 1 tsp of ammonium hydroxide is about 5 grams. Your results may differ, but I wasn't as pleased with ammonium hydroxide.

      I'm working on a new technique, but it's not finished yet. It involves blending two different syrups. When you use an acid like lemon juice, it will make the sugar dehydrate more quickly. This is where you get the "burnt sugar" and "dark fruit" flavors in the syrup. You'll get more coffee/chocolate flavors by excluding acid, and using a strong base like calcium hydroxide.

      I hope to release my new technique soon, but I haven't had much time to work on it lately.

  2. Thanks. I'm more relaxed about making my first candi syrup now.:)

    One more question: Have you already tried using ammonium-bicarbonate?

  3. Very good blog. You can also invert sucrose with Invertase enzyme. It comes from yeast. It's 100 % natural and works very well. If you want to avoid acid to help keep the pH higher for the Maillard reactions, this is a good way to go.

    Search on the web for the following paper. "The Maillard Reaction
    Application to Confectionery Products"

  4. Thanks Richard, I'll check that out!

  5. This comment has been removed by the author.

    1. Here is another facinating paper that I just finished reading describing the flavor profile of different amino acid-glucose maillard reactions. Note how many of them match the flavor of Belgian Candi Sugar.

      "Sensory aroma from Maillard reaction of individual and combinations of amino acids with glucose in acidic conditions"

  6. Hey Nate I PMed you on homebrewtalk but didn't get a response, so I figured I'd try you here =)

    Did you ever make any progress on you D2 recipe? I saw you were developing a new one but I can't find it anywhere and I'm really interested in it.

    1. Made a batch with your H recipe and results seems very promising, so thank you! Still hoping to hear from you someday =)


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