Making Belgian candi syrup
Belgian candi syrup is sugar that has been inverted and then darkened through Maillard reactions and caramelisation. It ferments almost completely, so it adds colour and flavour without making a strong beer heavy. Making it at home takes an evening and a good thermometer.
Candi syrup is cooked sugar, not table sugar
Belgian brewers have used sugar in strong ales for generations. It lets a tripel reach 8 or 9% ABV while staying dry and drinkable. Plain sugar adds alcohol and nothing else. Dark candi syrup adds alcohol plus flavours of raisin, toffee, dark fruit and a hint of roast, which is why it sits at the heart of a good dubbel.
The syrup is made in two stages. First the sucrose is inverted: split by heat and a little acid into glucose and fructose. Then a small amount of alkaline nitrogen source raises the pH and feeds Maillard reactions, which build colour and flavour as the syrup holds at high temperature.
You need four ingredients and a thermometer
For roughly 1.25 kg of finished syrup:
- White sugar: 1 kg
- Water: 250 ml, plus more later
- Citric acid: half a teaspoon, or the juice of half a lemon
- Diammonium phosphate (DAP) yeast nutrient: 1 level teaspoon, around 5 g
Use a heavy, light-coloured steel pan so you can judge colour. A digital probe thermometer is essential. Guessing sugar temperature by eye is how batches burn.
Some homebrewers use a pinch of food-grade lime or baking soda instead of DAP. DAP is the more common choice because its ammonium nitrogen drives the Maillard browning.
Colour builds between 120 and 135 °C
The method is simple but slow:
- Dissolve the sugar in the water with the acid. Heat to about 115 °C and hold for 15 to 20 minutes to invert it.
- Dissolve the DAP in a spoon of water and stir it in. The syrup will foam up, so keep the pan less than a third full.
- Hold between 120 and 135 °C, stirring occasionally. When the temperature creeps above 135 °C, add a tablespoon of water to pull it back down.
- Watch the colour move from pale straw through amber to deep mahogany. Light syrup takes 30 to 45 minutes. Dark syrup can take two hours or more.
- When you have the colour you want, take it off the heat. Carefully stir in 200 to 300 ml of very hot water to thin it.
Taste a drop on a cold spoon as you go. Dark syrup should taste of toffee and dried fruit, never acrid or burnt.
Hot sugar is the most dangerous thing in a homebrew kitchen
Sugar at 130 °C sticks to skin and keeps burning. Wear long sleeves and closed shoes, keep children and pets out of the kitchen and never leave the pan. The moment of adding water at the end is the riskiest. Cold water hitting hot syrup spits violently. Use water that is already near boiling, pour it slowly down the side of the pan and stand back.
On a gas stove in an Indian kitchen, a low steady flame works better than high heat. Thin steel pans develop hot spots that scorch the base before the rest of the syrup has coloured.
Use it for 10 to 20% of the fermentables
Candi syrup is close to fully fermentable. As a rough guide, 1 kg of plain sucrose dissolved in 20 litres adds about 19 gravity points (around 4.8 °P). Homemade syrup carries some water, so allow roughly 15 points per kg in 20 litres and confirm with a refractometer or hydrometer reading of the wort.
Most Belgian-style recipes use syrup for 10 to 20% of the fermentable extract. A 20 litre dubbel at 1.064 might use 0.6 to 0.8 kg of dark syrup alongside Pilsner malt and a little of a specialty malt such as Weyermann Abbey malt. Go above 20% and the beer can turn thin and hot.
Add it late and feed the yeast well
Stir the syrup in during the last 10 minutes of the boil so it dissolves and stays sanitary. For very strong beers some brewers add part of it to the fermenter once primary fermentation has slowed. Yeast takes up simple sugars before maltose. Feeding the sugar late lets it work through the maltose first, which can help it attenuate fully.
Strong Belgian worts are hard on yeast. Pitch plenty of healthy cells and start most Belgian strains around 18 to 19 °C before letting them rise. Our guide to making a yeast starter shows how to build the cell count. Knowing exactly how sugar additions change yeast stress, attenuation and ester profile is the sort of thing a recipe sheet leaves out.
Store it cold and use it within a few months
Pour the finished syrup into clean, hot glass jars and seal them while still warm. Kept in the fridge it lasts several months. The low water content keeps most microbes out, but in a hot Indian kitchen a jar left out can still ferment or grow mould once opened.
Make one dark batch before brew day
Make a single 1 kg batch of dark syrup this weekend, a few days before you brew. Taste it against a spoon of plain sugar. If it tastes of raisin and toffee, it is ready for your next dubbel.
Common questions
What is Belgian candi syrup made from?
Sucrose that has been inverted with a little acid, then darkened with a nitrogen source such as diammonium phosphate at 120 to 135 °C.
How much candi syrup goes in a dubbel?
Usually 10 to 20% of the fermentables. In a 20 litre batch at around 1.064 that is roughly 0.6 to 0.8 kg of dark syrup.
Is candi syrup the same as caramel?
No. Caramel is sugar browned by heat alone. Candi syrup also uses Maillard reactions from the added nitrogen, which give dried fruit flavours.
When should I add candi syrup?
In the last 10 minutes of the boil. For very strong beers some brewers add part of it to the fermenter as primary fermentation slows.
