Mold in glass bottles

[LCH]

I just opened 3 cases of last years syrup (36 bottles) to give out as Christmas presents and 17 of them had mold. I use a hydrometer to test the finished syrup and I fill the bottles directly from a filter tank on a propane burner. So the syrup should be going in at the correct density and above 180 degrees. Every year I have some bottles with mold (1 out of every 12 or so). But this year it is bad. I stored them in an underground concrete room under my back porch, which does get warm and moist during the summer. Does anyone have any suggestions on how I can eliminate my mold problem?

[DrTimPerkins]

Every year I have some bottles with mold (1 out of every 12 or so). But this year it is bad. I stored them in an underground concrete room under my back porch, which does get warm and moist during the summer.

The storage conditions won't affect whether or not you have mold, but could affect the growth rate some (temperature, not humidity). Mold is a far bigger problem in glass. Even going in at 180 deg F, the thermal mass of the glass cools the syrup off quite quickly, so that the entire bottle doesn't get hot enough. Some people will preheat the glass in an oven or hot water bath....this helps some, but glass, especially the smaller sizes, is frequently problematic.

Do you tip the bottles up after filling to heat up the cap? Are you sure your temperatures are hot enough (should be 180-190 deg F going into the bottle) throughout the entire canning process?

[TunbridgeDave]

The syrup is cooling too fast in the glass to sterilize and seal it. You got find a way to preheat the glass in boiling water or something b4 filling them. I checked a nip one time when I was canning. The syrup in the canner was 190 and after filling the nip I stuck an thermometer in it and it was only 140. Bigger glass doesn't seem to be as much of a problem.

[Jeff E]

Pretty well covered by everyone, but one more point.
I dont bottle to far ahead of need. That way the syrup that is going to customers has been bottled days or weeks before delivery, rather than months.
Storing hot packed drums works well, and you can always skim that bulk syrup if needed, before heating and bottling.

I dont reboil the syrup, just get it to 190-195. Then use a water jacketed bottler to hold the temp at 185 minimum.
This seams to be a good practice as I have not had a returned, moldy bottle in thousands going out.

[Scribner's Mountain Maple]

When I switched to glass this happened to me as well. For the pint and half pint sizes (and smaller) I make sure it is 190-195 going into the container and as Dr. Tim suggested i tip them over. Even going one step further by setting them on their side for 5-10 minutes to make sure the seal is completely heated. Then when I stand them back up I always try to give the caps another 1/4 to 1/2 turn to keep it tight. This works for me and I don't even preheat the bottles (I would preheat if it was easy for me to do). I think 190-195 is key for the little containers.

Ben

[lpakiz]

To continue on JeffE thought. I would want to know if there is a problem with mold. Therefore, I fill well ahead of time.
I would not want a customer to buy a bottle of recently bottled syrup and put it on the shelf (for what ever reason) for several months or even a year, and then discover there is mold on it.
I want it stored at my place so that I can see, before it is delivered, that every thing is all right.
I think if it is done right, the length of storage time is not an issue.

[Paddymountain]

concerning bottling with glass we preheat ours in the oven at 170 or 180 before we bottle. then as others we lay on side for 5 mins or so. we only had one get mold on this year, and am wondering if we fingered the inside of the cap during handling.

[adk1]

Put your glass in the oven and heat them up at 200 for awhile..pull out hot (if possible) and start filling using 190 degree syrup. Glas cools down so fast not getting enough contact time to steralize

[ennismaple]

The conditions where the syrup was stored can also have an impact. If the cases were stored in a room where the temperature fluctuates a lot what can happen is the water vapour in the air gap at the top of the bottle will condense and vapourize over time, causing a very thin film of watery syrup on the top. This thin layer of not-to-density syrup is what molds.

Of the thousands of bottles we filled this year the only ones we had problems with were 250 and 500mL maple leaf glass and 125ml glass. For each, the volume to surface area ratio is not very high so the 185 F syrup cools rapidly. Even at that, we only had issues with one or two bottles that had been on the shelf for 5 or 6 months.

[LCH]

Thanks for your help. It looks like it must be a problem with not preheating the bottles. I put them next to the evaporator stove pipe and I do invert them immediately after filling, but I am filling the jars in my barn (where the evaporator is). So to be safe, I need to figure out a way to keep the bottles hot and to be safe I will store them in a room with less fluctuation in temperature. I guess the temp varies between 80 degrees in the summer to as low as 50 degrees in the winter where I store them now.