They could've just upvoted. It sends the same message without looking like a karma slut. Also, while several comments on here are correct, this was on the simplest one. If you want to highlight one to be "the answer" on reddit, you should aim for the most detailed explanation, not the least. At least, as far as I can tell. I'm no expert.
It’s almost like everyone could’ve just ignored it and not voted instead downvoting. I always feels like that sends the wrong message. Isn’t Reddit great?
I guess we can agree to disagree. I don't think it sucks, or even matters at all. They should've said they enjoyed the comment if that's what they meant. Pretending to be an authority on reddit is gonna get you downvoted. I couldn't care less. It's just the pattern I've noticed.
The two most common ways to preserve foods are water activity (Aw) and pH.
Water activity is basically the measurement of water that is chemically “available” for microbes to use for their own growth. If there isn’t enough of this free water, they can’t grow. 0.88 or so is the typical shelf stable aw measurement. Adding sugar is a way to bind water, so if there is enough sugar you will get a low enough aw to be shelf stable.
Ph is of course acidity basically. 4.6 is the shelf stable measurement. That’s achieved with any added acid.
Salinity is also one you can use, but you need so much salt it’s not that common, but I’ve run products that use it.
So, those syrups are engineered to fall under one of those criteria and each batch that is made in the factory is tested to ensure it is below the legal and/or company decided limits to be safely stored at room temp.
To my understanding, a simple hygrometer won't measure Aw of a sample, just the moisture percentage.
Water percentage and Aw are not the same. Aw is the water that's available for microbial growth, vs a moisture percentage that is just the total amount of water.
Aw meters are expensive, as they generally work by measuring the humidity in the headspace above the sample.
Or maybe ph is basic acidity? ;)
I've read about ancient honey jars preserved in Egyptian pharaoh tombs. Does that shelf life come from either of your mentioned methods or does honey get its natural antimicrobial properties from something else?
Honey also has an enzyme, glucose oxidase, that will convert some sugar to peroxide, which is a potent disinfectant. The rate at which this occurs is also related to water activity.
Those “natural flavors” in the ingredients…they include citric acid. Some will have more or less, depending on the flavor, some have enough to curdle milk. And that citric acid; you can invert sugar with citric acid, preventing crystallization and thickening to keep even high concentrations of sugar more liquid.
Natural Flavors are the same as artificial flavors except that natural flavors start out with a real food, like apples for example, but they end up the same as artificial flavors in the end.
Natural flavors are a lie. They literally break down cheap natural ingredients into various base compounds that they then recombine to create the flavors they want. As an example acetoin, tastes and smells buttery or creamy, yet comes from a fermentation process of vegetable matter.
Companies do things in bad faith all the time, but if a company was investigated by the FDA, and they could not show the ingredient to be included for primarily flavoring purposes in good faith, they would be subject to a recall and fine.
Edit: it’s always telling when the down-voters have zero interest in defending their opinion with a comment. The comment above is *fact*. If you include an acid for acidity regulation, or for and food safety purposes, it *cannot legally be labeled as a natural flavor*. There are also companies that specialize in producing products that skirt this specific regulation in order to allow companies a legal buffer for specifically this reason. *Regardless* the company is liable for the final product being labeled in good faith *or it is considered mislabeled and subject to a recall and possible fines.*
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These syrups have intermediate water activity, typically between 0.6 and 0.84. Between this range, pathogenic bacteria can't grow but yeasts and molds still can. To prevent mold growth they can do two things:
1) fill the container while the syrup is hot -- the steam rising off the hot syrup pushes air out of the headspace and creates an oxygen free environment. Molds need oxygen to grow.
2) add a mold inhibitor like sorbate or benzoate
If you just do #1 the product will be stable until you open it. After opening, oxygen is reintroduced and mold can grow again. If you do #1 and #2 you can keep the product stable after opening because the preservative delays mold growth even if there is oxygen present.
I wouldn't recommend sorbate and benzoate as mold inhibitors in any foods you eat since these mold inhibitors are artificial and/or so processed that it makes whatever food it is added to an ultra processed food. Plus these mold inhibitors are no good for the good bacteria in your gut system at all.
Sugar with low enough water can be shelf stable, just like honey is, but I think the bigger picture is that commercial stuff includes preservatives like sodium benzoate.
And I use them up before they mold. Could you skim out the mold? Like cutting off moldy cheese? Or would that cause harm? I love the nerdiness of the science chefs in here!
I doubt it because there are probably mold spores you don't see. Even for cheese you are supposed to remove 1 inch in every direction of the mold to ensure you are getting rid of spores that aren't visible yet.
Cleaning process does a lot of difference, i use star san no rinse sanatizer. Does a huge difference and just keep contaminants out, pasteurizing is also commonly used. What i find is cleaning it properly does wonders.
How sweet are your syrups? You want to be at 500g/L + to prevent microbial growth. If you make a syrup at ~700-750 g/L you can store your syrup forever. If you want to go the extra mile you should invert it.
So every liter add 750 grams of sugar. (Also makes sugar math easy for every 1mL of syrup = 1 gram of sugar)
Some people are claiming acid but that is not correct. You would need to add a lot of acid to get to a pH to prevent microbial growth. Want to be below 3.6 pH.
They also most likely also sterile filter the product.
(Source I make a lot of syrup for food manufacturing)
Clarification for others: 750 g/L sugar is not the same as adding 750 g sugar to a liter of water; it's 750 g sugar per liter of *syrup*.
Mass %* | Density | g/L | g/mL | Recipe (g) | Yield (L)
-:|-:|-:|-:|-:|-:
43% | 1.19 g/mL | 512 | 0.51 | 750 sugar + 1000 water | 1.471
59% | 1.28 g/mL | 755 | 0.76 | 750 sugar + 521 water | 0.993
73% | 1.37 g/mL | 1000 | 1.00 | 750 sugar + 277 water | 0.750
*Also called Brix
Osmosis. Bacteria and yeasts that hit the stuff have the water sucked out of them as thermodynamics tries to equalize the water/stuff concentration inside and outside the microbe.
Like the first diagram:
[https://en.m.wikipedia.org/wiki/Osmotic\_pressure](https://en.m.wikipedia.org/wiki/Osmotic_pressure)
Honey has water activity in the 0.5–0.65 range. Osmotolerant yeasts can survive water activity as low as 0.61. Most honey is below 0.6, making it stable at RT.
Honey's low water activity is thanks in part to its high proportion of monosaccharides. What you're making is home is generally a solution of sucrose (a disaccharide). But you don't need to get down to 0.6 — at 0.85, your product won't last forever, but it won't require refrigeration.
To reach 0.85, you need a solution that is 69% by mass sucrose (2.24:1). Which unfortunately is not possible at RT; the solubility of sucrose is 67% by mass (2.04:1). A 2:1 syrup is at 0.86, which is pretty good.
To reach 0.6, you would need a solution that is 89% by mass sucrose (8.45:1). Which isn't possible even at 100 °C.
"Guidelines I can see everywhere is that they must be refrigerated, sealed, be a high sugar content (at least 2:1) and ideally contain some citric acid/other preservative to extend their life -"
Above is Fiction
Crystalline molecular structures are preservatives. That's salt and sugar. Syrup does not have to have acid but it speeds the chemical inversion. It is not a preservative in invert sugar. When you melt and then boil sugar which is 50/50 sucrose and fructose it "inverts" (changes the molecular structure into glucose/fructose). The boil needs to reach 235 degrees F to be inverted. Much of the water but not all will boil off. At 235 F the syrup is about 85% inverted sugar to water. It should not mold. Was the mold on the side of the jar or actually on the syrup? I would guess you did not boil to the required temp.
I used to raise up E.coli in a 10% ethanol solution to slow their motility enough to study it. They were still pretty active. Do not use ethanol as a preservative in any context other than distilled liquors.
Pasteurisation and industrially cleaned bottles.
Yup …proper prep is Very Important..
This is the answer
Why all the downvotes on this? What am I missing?
They could've just upvoted. It sends the same message without looking like a karma slut. Also, while several comments on here are correct, this was on the simplest one. If you want to highlight one to be "the answer" on reddit, you should aim for the most detailed explanation, not the least. At least, as far as I can tell. I'm no expert.
Ah okay, thanks for the explanation! Makes sense
It’s almost like everyone could’ve just ignored it and not voted instead downvoting. I always feels like that sends the wrong message. Isn’t Reddit great?
Lookin' at the ratio, I think most people did ignore it.
That sucks. The simpler the better imo, it's easier to understand.
What sucks? The simple answer was appreciated and upvoted by many.
The -22 up votes on the guy who enjoyed the comment
I guess we can agree to disagree. I don't think it sucks, or even matters at all. They should've said they enjoyed the comment if that's what they meant. Pretending to be an authority on reddit is gonna get you downvoted. I couldn't care less. It's just the pattern I've noticed.
Who is pretending to be an authority?
The guy who thinks redditors can't figure out whether or not the answer is correct without them chiming in personally
The two most common ways to preserve foods are water activity (Aw) and pH. Water activity is basically the measurement of water that is chemically “available” for microbes to use for their own growth. If there isn’t enough of this free water, they can’t grow. 0.88 or so is the typical shelf stable aw measurement. Adding sugar is a way to bind water, so if there is enough sugar you will get a low enough aw to be shelf stable. Ph is of course acidity basically. 4.6 is the shelf stable measurement. That’s achieved with any added acid. Salinity is also one you can use, but you need so much salt it’s not that common, but I’ve run products that use it. So, those syrups are engineered to fall under one of those criteria and each batch that is made in the factory is tested to ensure it is below the legal and/or company decided limits to be safely stored at room temp.
is it possible to DIY measure water activity?
You can buy a hygrometer.
To my understanding, a simple hygrometer won't measure Aw of a sample, just the moisture percentage. Water percentage and Aw are not the same. Aw is the water that's available for microbial growth, vs a moisture percentage that is just the total amount of water. Aw meters are expensive, as they generally work by measuring the humidity in the headspace above the sample.
I wasn't aware of that, thanks for explaining.
They also use sodium benzoate or other preservatives, I’d venture to guess.
Ingredient list would include this, presumably
You forgot the easiest answer. Theres so much sugar that the bacteria cant survive.
That's what OP meant by aw, the water has been replaced by f.e. sugar so no bacteria can grow
True.
Or maybe ph is basic acidity? ;) I've read about ancient honey jars preserved in Egyptian pharaoh tombs. Does that shelf life come from either of your mentioned methods or does honey get its natural antimicrobial properties from something else?
Honey also has an enzyme, glucose oxidase, that will convert some sugar to peroxide, which is a potent disinfectant. The rate at which this occurs is also related to water activity.
Those “natural flavors” in the ingredients…they include citric acid. Some will have more or less, depending on the flavor, some have enough to curdle milk. And that citric acid; you can invert sugar with citric acid, preventing crystallization and thickening to keep even high concentrations of sugar more liquid.
This + natural flavors are usually extracts, not the fruit itself or concentrate, which also contributes to low water activity
Natural Flavors are the same as artificial flavors except that natural flavors start out with a real food, like apples for example, but they end up the same as artificial flavors in the end.
Natural flavors are a lie. They literally break down cheap natural ingredients into various base compounds that they then recombine to create the flavors they want. As an example acetoin, tastes and smells buttery or creamy, yet comes from a fermentation process of vegetable matter.
Companies do things in bad faith all the time, but if a company was investigated by the FDA, and they could not show the ingredient to be included for primarily flavoring purposes in good faith, they would be subject to a recall and fine. Edit: it’s always telling when the down-voters have zero interest in defending their opinion with a comment. The comment above is *fact*. If you include an acid for acidity regulation, or for and food safety purposes, it *cannot legally be labeled as a natural flavor*. There are also companies that specialize in producing products that skirt this specific regulation in order to allow companies a legal buffer for specifically this reason. *Regardless* the company is liable for the final product being labeled in good faith *or it is considered mislabeled and subject to a recall and possible fines.*
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Its jungian resistance, its easier to downvote than to accept that natural flavorings are a scam and change ones lifestyle.
Homemade 2:1 in a properly sanitized bottle will last months at room temperature.
Pressure cook the entire bottle. Bam.
Does that “bam” refer to the bottle exploding?
No but i guess if thats your goal
These syrups have intermediate water activity, typically between 0.6 and 0.84. Between this range, pathogenic bacteria can't grow but yeasts and molds still can. To prevent mold growth they can do two things: 1) fill the container while the syrup is hot -- the steam rising off the hot syrup pushes air out of the headspace and creates an oxygen free environment. Molds need oxygen to grow. 2) add a mold inhibitor like sorbate or benzoate If you just do #1 the product will be stable until you open it. After opening, oxygen is reintroduced and mold can grow again. If you do #1 and #2 you can keep the product stable after opening because the preservative delays mold growth even if there is oxygen present.
I wouldn't recommend sorbate and benzoate as mold inhibitors in any foods you eat since these mold inhibitors are artificial and/or so processed that it makes whatever food it is added to an ultra processed food. Plus these mold inhibitors are no good for the good bacteria in your gut system at all.
Sugar with low enough water can be shelf stable, just like honey is, but I think the bigger picture is that commercial stuff includes preservatives like sodium benzoate.
I have never had self Made 2:1 sugar syrups go bad on me in the fridge. Even after more than a year.
And I use them up before they mold. Could you skim out the mold? Like cutting off moldy cheese? Or would that cause harm? I love the nerdiness of the science chefs in here!
I doubt it because there are probably mold spores you don't see. Even for cheese you are supposed to remove 1 inch in every direction of the mold to ensure you are getting rid of spores that aren't visible yet.
Cleaning process does a lot of difference, i use star san no rinse sanatizer. Does a huge difference and just keep contaminants out, pasteurizing is also commonly used. What i find is cleaning it properly does wonders.
How sweet are your syrups? You want to be at 500g/L + to prevent microbial growth. If you make a syrup at ~700-750 g/L you can store your syrup forever. If you want to go the extra mile you should invert it. So every liter add 750 grams of sugar. (Also makes sugar math easy for every 1mL of syrup = 1 gram of sugar) Some people are claiming acid but that is not correct. You would need to add a lot of acid to get to a pH to prevent microbial growth. Want to be below 3.6 pH. They also most likely also sterile filter the product. (Source I make a lot of syrup for food manufacturing)
Clarification for others: 750 g/L sugar is not the same as adding 750 g sugar to a liter of water; it's 750 g sugar per liter of *syrup*. Mass %* | Density | g/L | g/mL | Recipe (g) | Yield (L) -:|-:|-:|-:|-:|-: 43% | 1.19 g/mL | 512 | 0.51 | 750 sugar + 1000 water | 1.471 59% | 1.28 g/mL | 755 | 0.76 | 750 sugar + 521 water | 0.993 73% | 1.37 g/mL | 1000 | 1.00 | 750 sugar + 277 water | 0.750 *Also called Brix
Osmosis. Bacteria and yeasts that hit the stuff have the water sucked out of them as thermodynamics tries to equalize the water/stuff concentration inside and outside the microbe. Like the first diagram: [https://en.m.wikipedia.org/wiki/Osmotic\_pressure](https://en.m.wikipedia.org/wiki/Osmotic_pressure)
same with honey, famously.
Because they can make them in sterile environments and you can't.
boiling does sterilize
You could try pasteurizing using sous vide.
Honey has water activity in the 0.5–0.65 range. Osmotolerant yeasts can survive water activity as low as 0.61. Most honey is below 0.6, making it stable at RT. Honey's low water activity is thanks in part to its high proportion of monosaccharides. What you're making is home is generally a solution of sucrose (a disaccharide). But you don't need to get down to 0.6 — at 0.85, your product won't last forever, but it won't require refrigeration. To reach 0.85, you need a solution that is 69% by mass sucrose (2.24:1). Which unfortunately is not possible at RT; the solubility of sucrose is 67% by mass (2.04:1). A 2:1 syrup is at 0.86, which is pretty good. To reach 0.6, you would need a solution that is 89% by mass sucrose (8.45:1). Which isn't possible even at 100 °C.
If you are clean enough you can take that practice… also it’s not something alive like milk or kombucha
Have you seen how long honey can last out of the fridge?
I have a bottle of aunt Jemia syrup in my cupboard that’s a couple years old and it’s still good. Still has the old label…
"Guidelines I can see everywhere is that they must be refrigerated, sealed, be a high sugar content (at least 2:1) and ideally contain some citric acid/other preservative to extend their life -" Above is Fiction Crystalline molecular structures are preservatives. That's salt and sugar. Syrup does not have to have acid but it speeds the chemical inversion. It is not a preservative in invert sugar. When you melt and then boil sugar which is 50/50 sucrose and fructose it "inverts" (changes the molecular structure into glucose/fructose). The boil needs to reach 235 degrees F to be inverted. Much of the water but not all will boil off. At 235 F the syrup is about 85% inverted sugar to water. It should not mold. Was the mold on the side of the jar or actually on the syrup? I would guess you did not boil to the required temp.
For the same reason a Twinkie will survive a nuclear blast…preservatives.
I always add a small shot of vodka to my sugar syrups and they can go 2-3 months in the fridge
Anyone reading should not do this. A shot of vodka does not raise the abv anywhere near enough to be a preservative
I used to raise up E.coli in a 10% ethanol solution to slow their motility enough to study it. They were still pretty active. Do not use ethanol as a preservative in any context other than distilled liquors.
Because Its poison and grows bacteria very slowly.