Mold on top of syrup

[sweet willy]

What are some of the reasons mold forms on top of maple syrup. I have my own opinions, just wondering what everyone else thinks.

[happy thoughts]

on my short list...

-syrup that wasn't brought to the right density
-mold spores introduced during bottling especially on the inside cap
-improper storage

[Greenwich Maple Man]

on my short list...

-syrup that wasn't brought to the right density
-mold spores introduced during bottling especially on the inside cap
-improper storage

I think you are right on. Also not being at the proper hot packing temp. will cause it to mold as well.

[happy thoughts]

another I just thought of- underfilling the container. The more air in the bottle the more oxygen to allow mold growth. I think that's one reason for the narrow necks in traditional syrup containers, but I'm just guessing..

[sweet willy]

I should've added that it seems to happen more in glass than any other, I'm thinking the glass cools syrup to fast.

[MN Jake]

I cant figure out where my replies are going, sorry if they are showing up somewhere.....Would it make sense have a pot of glass jars lightly simmering at bottling time or is that wasting time

[happy thoughts]

I can't say I've noticed that problem with glass. I'm just a small time home use only maker and in 6 years have only had one bottle get moldy. I use glass almost exclusively.

Any mold spores in the syrup should have been long killed by the high temp of the syrup. I believe the temp needed to kill mold is around 140F. It's more likely imho, that mold was introduced somewhere in your bottling process, either in the container or on the inside lid or in the air space left in the container.

[Dave Puhl]

Air..plain and simple.....I got small sealed glass bottle full of syrup six years old and is still the same as when I put it in...

[sweet willy]

Makes sense, we will have to pay more attention to the air space in the glass, and make shur the hot syrup comes in contact with all the glass bottles. Thanks.

[happy thoughts]

Don't forget to invert the bottle after capping and while the syrup is still very hot. Again, I'm assuming something, but I think that should heat kill any mold spores that may have fallen on the cap. Also, since I reuse containers, I treat them just as I would in normal canning by sterilizing clean jars and caps in boiling water for 15 minutes just prior to bottling. I also throw my ladle and funnel in there to sterilize along with the bottles.

[Brent]

If the glass is cool and the volume is small the syrup can cool too fast to sterilize the inside, particularly at the neck and cap.
The 50 ml small maple leaf shaped bottles are the worst in my mind. Lots of glass and only a few tablespoons of syrup.
I have never measured the chill effect but I'll bet that before you get the cap on the syrup is down to 160 degrees or so.
Got to pre-heat the bottles if they are on the small side.

My wife pre-heats our small bottles in the kitchen oven and we take them to the sugar shack in a cooler to keep them hot.
The big ones we just warm to avoid thermal shock .... after having a few shatter on us. Since we started pre-heating bottles
we have never had mould