mold in syrup

[MountMapleQC]

We have a small maple syrup hobby operation. We only make about 20 gallons of syrup per season on a homemade evaporator the old-fashioned way. When we take the syrup off at 219 degrees, we are outdoors. We pour it through a pre-filter and a thick wool filter into a 4 gallon stainless steel tote. From there it gets poured into individual glass bottles. This is all done quickly. My thinking was that because the syrup is so hot, it should kill any bacteria in the bottles, preventing mold. I noticed a bit of mold the first year settling at the top of the syrup and assumed it was because the top of the bottle was still ambient temperature when we poured it, being an environment for bacteria to survive. The next year, I turned all of the bottles upside down immediately after syrup was poured to try and kill any bacteria in the upper part of the bottle with the heat from the syrup. My understanding is that bacteria dies at temperatures above 140. When the syrup is poured into the bottles it is still well above 140. Why am I still getting mold growing? Any help would be appreciated! Thanks

[mainebackswoodssyrup]

You’re doing the right thing by turning the bottles upside down immediately. Leave them that way for at least a minute. 180-190 degrees is the range for bottling syrup to kill off anything. Some people also preheat glass. We do not do that but we do make sure the glass is stored and comes from room temperature so it doesn’t cool the syrup too quick.

[maple flats]

You need a way to keep the syrup above 180F as it goes into the bottle and cold glass can be an issue, warm the glass to prevent that being an issue.
Just filtering it thru 4 prefilters and a wool filter can allow the syrup to cool too much, then putting it into a 4 gal SS tote can be another issue, too many ways for the 219F syrup to cool below 180. If in doubt, use a thermometer to verify, I'd be surprised if you are not significantly below 180F as you put the syrup into the glass.

[DrTimPerkins]

https://mapleresearch.org/pub/04hrt14a2/

[Buffalo Plaid]

Are you sure it’s syrup? You may be bottling it light. Check it with a hydrometer to be sure

[ecolbeck]

Are you sure it’s syrup? You may be bottling it light. Check it with a hydrometer to be sure

That was my first thought too.

[Pdiamond]

As previously mentioned you need to make sure your syrup is at 66.9 brix not judge it just by temperature alone. A syrup hydrometer will be a big help with this part of the process.

[David Wayne]

I am hobby also, I use a murphy cup with my hydrometer so I am sure I have syrup. Then I filter it into a 20qt. stainless pot using flat filters in a collander.
The stock pot is slightly floating in a larger pot of water that I keep at a low boil, This keeps the syrup hot while I am canning- into preheated jars and lids from boiling water. I have syrup in the fruit room that is from 2019, only find mold if I come across a jar that has lost it's seal.

David

[MountMapleQC]

Thank you. These are very helpful tips!