Preserving Your Syrup
Once you’ve made your cocktail syrup, you need to figure out a way to preserve it if you’re not going to use it right away. And there are a number of ways you can approach this.
First off, let’s take a look at the two biggest culprits that cause syrups to go bad: bacteria and mold.
These are things that are floating around or growing all over the place, especially in our kitchens and refrigerators. So the first step in preserving your syrup actually happens before you make it – and that is to thoroughly cleanse your kitchen workspace before you produce. This means you want to wipe down all surfaces with an antibacterial cleanser, and certainly be sure to follow other best-practices like washing your hands and using clean pots and utensils.
Syrup Temperature Regulation
On the stove, one thing you can do to prevent bacteria from forming is to bring your syrup to a light boil. We’re not talking pasta water boil here. Just bring it up to a simmer where you’ve got little bubbles rising from the bottom of the pot and steam escaping from the surface. This indicates that you’re in the neighborhood of 212 degrees Fahrenheit, which is the boiling point of water.
The Case for Cooling
Chefs and caterers, generally want to chill down their pre-prepped food as quickly as possible once it’s cooked. And the thinking behind this is that bacteria and mold tend grow best in neutral temperatures, so the more quickly you bring that food from hot to cold, the smaller the window will be for bad stuff to get in there and grow.
Technically, this is also true for syrups, except, unless you’re going to use it all right away, you’re probably going to be storing it in the refrigerator in a clean, sealed container. So if you transfer your syrup to a carefully sterilized bottle or mason jar right away and seal the top, you don’t really need to worry about refrigerating until the first time you open it.
However, if you frequently make batched cocktails for events or social gatherings, you might need to chill down your syrup so you can batch your cocktail without warming up the other ingredients too much.
Bar Hack: The Double Chiller
One method we devised for really quickly chilling down syrup is something we call a “double cooler” because it works roughly the same way a double boiler works on the stove. If you’re melting chocolate, for example, you put your chocolate in a small saucepan, and you place that saucepan inside a slightly larger saucepan filled with boiling water, and this ensures that you’re not going to burn the chocolate.
The double cooler works the same way, and the real benefit is that you cool your liquid without diluting it. Use one of those large stainless steel mixing bowls that you can pick up on Amazon or at Ikea for cheap. Fill the bowl about halfway with cold water and large ice cubes, and then place your saucepan filled with syrup directly inside the bowl, making sure the water and ice are in contact with the bottom and sides of the pot.
Using this method, you can easily chill down a liter or two of syrup in about half an hour. It’s one of our favorite bar hacks, and now, it’s all yours.
There are a couple of things you can do to avoid bacteria and mold.
One is to make the pH (of level of acidity) in your syrup inhospitable to the little microbes that spoil it. For bacteria, this means lowering the pH by adding something like citric acid, which is basically just powdered lemon juice. So if you’ve got some citrus lying around, that can help, but you can also pick up citric acid for cheap on amazon, and believe me, a little goes a long way.
For mold, it gets a bit trickier because preventing that is more of a chemical thing, not just a pH thing. So if you really want to nerd out, check out mold inhibitors like potassium sorbate or sodium benzoate, both of which can be found on the ingredient lists of many canned or bottled products.
Finally, the richness or thickness of your syrup can play a role in avoiding spoilage. Formally, this property is measured using something called a BRIX score, which is based on the specific gravity of your liquid. And in normal language, basically what happens is the thicker your syrup is, the fewer water molecules are available to host microbes because they’re all stuck to sugar molecules.
In this respect rich simple syrups are better than regular simple syrups, so if you’re planning on storing your syrup in the fridge and using it over the course of a month or so, maybe consider using a rich simple syrup to avoid spoilage.
Measuring Specific Gravity
If you want to get a bit scientific with this, you can actually calculate the specific gravity of your syrup if you have a little digital kitchen scale. All you do is get your pyrex measuring cup, fill it with 2 cups or 500ml of water. Weigh that. Dump it out. And then fill it with an equal volume of syrup and weigh that. The syrup is going to be heavier than the water, logically, and to arrive at the specific gravity of your syrup, all you do is divide the weight of the syrup by the weight of the water. And you’re going to come out with some decimal that’s between one and two.
The Vodka Misconception
Before we move on to a few recipes and pro-tips for at home syruping, there’s one common misconception we’d like to clear up, and that is the use of vodka to prevent bacteria growth in syrups. Technically if you add a tablespoon of ethyl alcohol on top of your syrup, yes, that will float on top and prevent any bacteria from getting to your syrup. But so does a properly sterilized lid or cap. So there’s really no reason to use the vodka float method.
And if you’re thinking: well, I’ll just mix the vodka into the syrup instead of floating it, then yeah, that might help, but you’d need to add so much alcohol to your syrup to prevent bacteria growth that, by time you’re done, you’ve got more of a cordial or liqueur, and then you’ll have more alcohol in your cocktails than perhaps you were planning for. So forget the vodka, and focus on a clean workspace, a properly thickened syrup, and maybe some acidification if you want to preserve your syrups in a home setting.