Date syrup and palm sugar in beer

Different sugars, different flavours

Date syrup is made by cooking and concentrating dates. It is dark, thick and tastes of dried fruit and toffee. Its sugar is mainly glucose and fructose. Palm sugars are made by boiling down the sap of palm trees. Nolen gur, the winter jaggery of Bengal, comes from the date palm and smells of caramel and smoke. Palm jaggery, or karupatti, comes from the palmyra palm in Tamil Nadu and has a deeper, mineral sweetness. Both are mostly sucrose.

All of these ferment almost completely. What stays behind is a little flavour from the compounds formed when the syrup or sap was cooked. That is the reason to use them.

How much gravity each kilo gives

Pure sucrose adds roughly 46 gravity points per pound per US gallon. In metric terms, 1 kg of table sugar in 20 litres raises the gravity by about 0.019. Palm jaggery is mostly sucrose with some moisture, so it gives a little less, often around 0.015 to 0.017 per kilo in 20 litres.

Date syrup is usually about 70 to 75% sugar solids. Check the label or measure it on a refractometer. At 70% solids, 1 kg in 20 litres adds roughly 0.013. These are estimates: measure your wort before and after the addition and record the real figure for next time.

When to add them

The safest point is the last 10 to 15 minutes of the boil. The heat dissolves and sanitises the sugar. Jaggery in particular can carry wild yeast and bacteria from open-pan production, so we never add it raw to the fermenter.

Adding sugar after primary fermentation has slowed is another option. Yeast ferments the simple sugars after the harder malt sugars, which can help attenuation in a strong beer. Dissolve the sugar in a little water, boil it for five minutes, cool and add. Our guide to making Belgian candi syrup shows the same technique.

How much to use

Simple sugars dry a beer out. That is useful up to a point. Keep sugars to about 5 to 15% of the total fermentables in most beers. Strong Belgian ales may go to 20%. Beyond that, a beer can taste thin and hot.

For flavour you can actually taste, 10% is a good starting point. In a 20 litre batch with about 5 kg of malt, that is roughly 0.5 kg of palm jaggery or 0.7 kg of date syrup. The one floor detail worth noting: date syrup is thick and clings to the tin. Weigh the tin before and after pouring, or you will add less than you think.

Styles that suit each sugar

• Date syrup: a brown ale, dubbel or porter, where its dried fruit notes meet caramel and roast.
• Nolen gur: a winter ale or Belgian dark strong ale, where its smoky caramel shines.
• Palm jaggery: a strong golden or amber ale, or a stout with a mineral sweetness.

Light, clean lagers do not show these sugars well. Their flavour is subtle and needs a malty or yeast-driven beer to support it. Our guide to khandsari, cane sugar and other Indian sugars covers the cane-based options alongside these.

What the yeast leaves behind

It surprises many brewers that a sugar this flavourful can ferment almost to nothing. The sweetness goes; what remains are the cooked, caramel and smoky notes made when the syrup or sap was boiled down. In a finished beer those read as a faint toffee, raisin or smoke note in the background rather than as sweetness.

That has two consequences. First, a beer brewed with 10% palm jaggery will usually finish drier than the same beer made with all malt, by a few gravity points. If you want body, mash a degree or two warmer, around 67 to 68 °C, or add a little crystal malt. Second, the flavour is subtle. If you cannot pick it out, double the sugar share before you blame the ingredient.

Yeast choice matters too. A Belgian strain adds fruity esters that blend with date and palm sugar notes. A clean American ale yeast lets the sugar speak more plainly. Both are valid; choose before brew day.

Buying and storing in India

Nolen gur is seasonal. It is made in Bengal in the cold months and sold as a liquid (jhola gur) or as hard cakes (patali). It ferments and turns sour if stored warm, so refrigerate the liquid form. Karupatti comes as hard cakes and keeps well in an airtight jar. Date syrup is sold year-round in supermarkets and Middle Eastern grocers.

Check labels. Some products are blended with cane sugar or contain additives. For brewing, buy from a source that sells pure product. Taste a little before you commit a batch.

Making the sugar count

A sugar addition changes attenuation, body, alcohol and flavour all at once. Deciding how much to use and where to add it is a style decision rather than a recipe swap. That is where a structured style course pays for itself.

Your first step: dissolve 100 grams of palm jaggery in a litre of water, take a gravity reading, then work out how many points a kilo would add to your next batch.

Common questions

Is palm jaggery fully fermentable?

Almost. It is mostly sucrose, which yeast ferments completely. A little flavour from the cooking stays behind, which is why brewers use it.

How much gravity does 1 kg of sugar add to 20 litres?

About 0.019 for table sugar. Palm jaggery gives a little less and date syrup at 70% solids gives about 0.013.

When should I add jaggery to beer?

Add it in the last 10 to 15 minutes of the boil so the heat dissolves and sanitises it. Never add raw jaggery to the fermenter.