The word syrup has a more nebulous meaning than some may think. It might just remind you of the unnaturally sweet goop in the log cabin bottle that your mother gave you to put on your Eggo waffles in the morning. However, it includes such a vast array of food preps that it seems ambiguous to just call the liquid combination of water and sugar a syrup. It could be a simple syrup, a thick pouring syrup, or a glaze depending on sugar concentration. I’ve found that there really isn’t a lot of readily available information on the subject other than asking your local head pastry chef or just experimenting in the kitchen, of which I did both. Herein are my discoveries and it’s about to get nerdy!
When you dissolve sugar in a liquid the sugar forms hydrogen bonds which give the liquid viscosity and a smooth homogenous state of liquid. However you’ve probably noticed when you make sweet tea with cold liquid and add sugar that a lot of it will just settle on the bottom of the glass. This is because the tea does not have enough energy to cause the molecular motion necessary to dissolve so much sugar. It takes heat to do that and this is why we use simple syrups in cold drinks: because the sugar is already dissolved and ready to be dispersed in the drink!
For simple syrup, the age old ratio is 1:1 by weight which comes out to about 1 1/4 cups of sugar to 1 cup of water leaving the sugar concentration at 50%. You make this sweetener by heating water to boiling, shutting off the burner, then adding the sugar and mixing to dissolve. Some evaporation will occur, leaving you with a higher concentration of sugar but it is minimal. The texture of the liquid will be thicker than water, but not by much.
For a thicker syrup that is more akin to natural maple syrups, you’re looking for around 65-68% sugar. There are two methods that can be used for this I’ve found. The traditional method is to make a simple syrup and continue to let it boil until enough water evaporates to get you to the desired concentration of sugar. You can measure this by temperature, as the amount of sugar in the liquid is directly connected to the boiling point of the liquid. Higher concentrations mean a higher boiling point because sugar has a higher specific heat than water (meaning it takes more energy to get its molecules to do something). Candy thermometers will show states of the syrup through terms such as soft ball, hard ball, hard crack, etc. Unfortunately, I’ve never seen a thermometer that says syrup or glaze on it so that desired temperature is left in the hands of the capable chef. For 65% I’ve found 220º is just about right.
If you’re looking for a glaze that you can brush onto pastries or savories you’ll want anywhere from 70% to a whopping 75% for something the thickness of molasses. This is where my second method comes in that I’ve actually discovered is my favorite and I’ll tell you why. Instead of starting with a 1:1 ratio of sugar to liquid you start with a 2:1 in the sauce pan while the liquid is cold. This starts you at the pouring syrup concentration of 66% which means once it’s dissolved you’re done with the thick syrup and takes very little boiling time to get it to 70-75%. I find that this is a much more controlled way of getting to a glaze since pans, burners, and chefs all create uncontrollable variables as far as boil temperature is concerned. It is also much faster since there is barely any evaporation involved. I use this method almost exclusively to make my syrups and glazes. If you want to reduce it with the traditional method you’ll be looking at About 224-230º for a glaze but be careful because at 235º you’re at the end of the thread stage of the sugar:water composition and that’s where it starts setting up solid!
Don’t get discouraged if your syrup ends up too thick or too thin because it takes practice to get control over it. If you go too far on accident and it ends up too thick, just add a small amount of water while the liquid is cold to reconstitute it! When using acidic liquids, the second method works best as the acid can cause sugar to burn more easily resulting in a bitter outcome. Good luck, sugar!
Oh and if you’re wondering, maple sap starts out at about 3% sugar so to get one cup of velvety 65% syrup it takes 2.5 gallons of sap. No wonder why the real stuff is so expensive.