Sugar concentration vs spoilage

[m2salmon]

So you get let’s say 60 gallons of sap and boil it down, enough to sweeten your pans. Now you wait for the next run to boil again. I’ve read sap will spoil if it warms or is not boiled within a few days. Is the same true for concentrated sap in sweetened pans?

If it can take days to a week or more until another run with enough to boil, what do you do, just keep the sweet in the pans? Or do you drain into buckets or something that you can maybe put in the snow to keep colder?

[18mile]

Sweet in the pan an turn ropy within a couple of days

[VTnewguy]

Our sugarhouse is uninsulated so even between longer boils the sweet isn't exposed to warm temps. This usually only happens at the beginning of the season with the end of winter, start of spring. Once into the warmer temps I wouldn't be waiting to boil because it can spoil. I think the analogy used was to treat sap like milk.

[buckeye gold]

I don't worry about sweet until temps get in the mid 40s. It will hold a little better than sap since it has been boiled. If temps stay 35 or below it will hold for a few days. If it freezes into a slush then it can go even longer. If in doubt, start a small fire and bring it to a low or almost boil or drain and store in cooled storage. If I go a week I usually just finish my near syrup on propane. In a two pan system that is your syrup pan, or like me on a small hybrid hobby pan the whole thing. Sometimes we lose some sap or sweet. I learned a long time ago it's not sacred. Why produce a compromised product. If your selling, the parameters need to be pretty strict, but if it's home use then make your own choices.

[DrTimPerkins]

Spoilage will depend upon concentration, temperature and time. Typically if you're not boiling it'll either be because it is too cold (early season) between runs, or too hot (later season) between runs. The former is not really a problem since the cold will delay/prevent spoilage. When it is warm, you can fire up every 2-3 days long enough to bring the sweet to a boil and kill any microbes that might be getting started.

One way to help prevent spoilage is to make sure that you don't add any sap or water to the pan unless you boil it again. So at the end of the boil, don't add any unboiled sap to the pan. This also can extend to the float boxes which can act as reservoirs of microbes. Some boxes are located a bit away from the pans, so they never get really hot. If that is the case, draw off the sweet/sap in the boxes before you shut down using the drain usually located in the box and pour it into the pan, and/or draw off some boiling sweet from elsewhere in the pan and pour it into the box to sterilize the contents of the box. Otherwise anything that starts to grow in the box will spread throughout the pans. Make sure your feed lines are drained fully so unboiled sap doesn't contaminate the pan.

[m2salmon]

Thank you for the replies.

If you have a 2 pan setup and want to finish what you have in the syrup pan, you drain the flue pan into the front pan and close the valve. If you are out of sap which is why you are finishing the batch, do you keep dumping water in the flue pan to keep it from running dry, while finishing in the front pan?

[NhShaun]

That's what i usually do. Once i boil it down the most i can in the front pan I open the valve and let the water help push the syrup closer to the draw off valve. You get a little water mixed in your syrup but beats cooking it down on a propane burner for 3 or 4 hours.

[DrTimPerkins]

If you are out of sap ... do you keep dumping water in the flue pan to keep it from running dry, while finishing in the front pan?

Several ways to do it.

1. If the evaporator is small enough, empty all the contents of the flue and syrup pan into a smaller vessel (turkey cooker) and finish it all on there.
2. "Chase the sweet" by drawing down the depth in the pans as low as you dare, then run water into the fluepan (as if it were sap). This will steepen the gradient a bit and push a bit more syrup out. The amount you get out will depend on the size of your evaporator and whether you're boiling sap or concentrate. With sap you'll only get a little out, with concentrate you'll get more. It's all related to how "steep" the gradient is and how much you change it by introducing water. This method still leaves a good deal of sugar in the evaporator.
3. Once you've drawn off all you can and are out of sap, close off the valve between the flue and syrup pans, drain the flue pan (after the rig cools off) and put all the contents into the syrup pan. Put water into the flue pan. Boil without drawing off until the entire syrup pan is syrup....keep mixing among the partitions with a ladle as you do this to homogenize the entire contents of the syrup pan. Once it gets to syrup, let it cool off and drain the entire syrup pan. Then open the connection to the flue pan and flush out the syrup pan. Drain and clean both pans after the rig cools.

Option 2 is how we typically finish the season....no chasing the sweet and no loss of syrup with this method. We don't do it after each boil. You just need a good supply of water. It is a lot easier on an oil-rig than on a wood-rig though, since you can shut off the pan and it'll cool fairly quickly.

The other approach to preventing spoilage of the sweet if the weather is warm but you don't have any sap is to add some water to the flue pan and boil for 5-10 minutes every couple of days...just long enough to kill any microbes that start.

[m2salmon]

That all makes sense. Thanks again for all the help!