pH for sugar water?

>I seem to understand that people add vinegar to their syrup to lower the pH? Is this correct?

Some do. In my experience the vinegar sets off a feeding frenzy which can easily turn to a robbing frenzy.

> If so, could someone please explain why the pH needs to be lowered

Here are the studies on the subject of the microbes, all of which live best if the pH is not disrupted:

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033188

This one shows that there is a biofilm of Lactic Acid Bacteria (LAB) living in the gut of the bee that protects them from many diseases. Syrup disrupts this.

http://www.beeuntoothers.com/index.php/beekeeping/gilliam-archives

Here are a lot of studies by Martha Gilliam on the microbes that live on and around the bees and some of it points out that syrup disrupts those.

Why does syrup disrupt it? Likely one of the factors is the pH of the syrup, which is quite different from honey.

All of that said, while I manage bees to try to avoid feeding, I would always feed when the choice is between feeding and starving. There is nothing to be gained letting bees starve.

>and what is the pH level that we're looking for?

I shoot for 4.5

>Besides pH, is there any other reason to add vinegar?

It keeps the syrup from spoiling, but any other acid does and may not set off robbing so much. I use ascorbic acid (vitamin C) rather than acetic acid (vinegar).

Honey is acid because it is a mix of glucose and fructose which have loosely bound hydrogen ions as part of the sugars' six carbon chains.
Syrup (a solution of sucrose) is basic because there are fewer (ie negative log) hydrogen ions available.

Honey bees possess the enzyme to catalyze the hydrolysis of sucrose in their crop. This enzyme is added to syrup or nectar, and the syrup is inverted and becomes acid in reaction by the action of the bees ingesting it.

The bees possess everything they need to make honey in their crop from the inputs of nectar (a mix of sucrose, glucose and fructose). The addition of a hydrogen donor such as citric acid, or vinegar simply inverts the sugar in solution.

Inverting sugar "sweetens" it because a molecule of H20 is incorporated into the carbon rings in the process of hydrolysis. The bees use hydrolysis as a way of increasing the concentration of the raw nectar without evaporation.

Hydrolysis is splitting the double ring of sucrose in the weak middle link:::


Fructose in solution adds and loses hydrogen+ ions from the ring freely. Note that the sugar has a one or two carbon side chain, with an O-- atom occupying a ring position. The O bond with adjacent Carbon releases a H+ from a hydroxyl group. The nomadic H+ is what raises the log availability of H+ in the solution.


Ascorbic Acid is an unstable ring with loosely bound hydrogen

I have found that vinegar induces robbing.

You can feed unlimited amounts of simple sucrose syrup and the "honey" produced by the bees feeding on it will still be acid. It is acid because that is what fructose solution are intrinsically, not because of adulterants added to the syrup.

HMF is a degradation product of heated fructose. Toast or Roasted coffee are rich in the compound. It will form from any fructose source when exposed to temps over 120 F.
It is formed by low heat, leading to dehydration of the fructose hex (the H and OH groups are removed), and catalyzed by a weak acid source (which efficiently captures the hydroxyls to balance positive charge of the H+ released by the acid). If you want to efficiently make HMF -- follow the "natural" recipe of adding acid to syrup in the presence of heat.

HMF is absent in sucrose syrup.

You fix the blinky-eye problem by adding "Dark Energy" to Sucrose. This makes Bee Ray-bans, and the hep-cat bees don't blink.