What happens to defoamer?

[cray54]

I realize many things have been / are used as defoaming agents [and that their purpose in this context is to reduce foaming during the boiling process].

I understand Atmos 300K and safflower oil are two common ones. During the boiling process, what happens to these defoaming agents? Do they simply end up in the finished product in a very low concentration? Are they fully or partially "steam extracted"? Do they react with anything in the process? Etc?

Thanks,
Chris

[spencer11]

I don't know if this is right but it might be filtered out if its not evaporatored, think of filter aid, you put that in the syrup but it get caught on the filter(why it goes through easier) and isn't in the finished product

[PerryW]

A typical dose of a few drops of Defoamer boils off (evaporates) in a few minutes. That's why you should try to avoid putting in in your front pan if you expect a take-off within a few minutes.

[happy thoughts]

The temps reached in boiling syrup probably won't allow the oil to actually evaporate much if any. Some may be carried off with steam but I'd be pretty certain some is going to remain in the syrup. That's why peanut oil and butter aren't recommended because of food allergies even though the amount used may only be a few drops. And I've read that lard and other animal fats can go rancid in time giving syrup an off flavor so I think some defoamer can probably be expected to remain in syrup.

[PerryW]

I stand corrected. Looks like the boiling point of corn oil at around 470 deg F.

I guess I'm still wondering why I have to keep adding it, if it doesn't evaporate? I pretty much have to add it every 5-10 minutes to the back pan once I get going. If it doesm't evaporate, then why do I need to add it to the front pan?

Maybe the Doctor can chime in here??

[happy thoughts]

Just thinking out loud here Perry, I don't know for sure but I'd guess some is getting carried away by steam, my range hood gets greasy even if I manage not to burn dinner :), some may be splashing on the sides of the pan and hardening like seasoning on cast iron, some may be trapped in the fine scummy foam as you approach syrup. Since oil is lighter than water it's going to float on top so anything that's going on up top of the boil probably has something to do with it.

[PerryW]

I'm guessing there could still be some evaporation of the oil even though the boiling point of oil is much higher (though it may be insignificant).

The measured temperature of a liquid is proportional to the average of all the vibrating molecules. The temperature of individual molecules looks like a bell curve with the peak of the bell at the temperature, i.e. .....

That's why water will evaporate at room temperature. Some of the molecules in room temperature water are actually above the boiling point and they convert to a vapor and leave the container as water vapor.

I dunno though. I though someone told me the stuff boiled off so I'm just guessing here.

Just canning up 10 gallons of Fancy, 30 more to go. Batch #2 is heating up now!

[cray54]

I'll try to summarize posted ideas and some others:

[Note: I'm referring to Atmos 300K and Safflower Oil as defoamer in the discussion (since I think there are too many substances that could be used as "defoamer" to make statements that cover them all)]


Defoamer needs to be added as boiling continues, so it must lose its defoaming characteristics or leave over time
Defoamer can remain in the finished product

Does this mean too much was used during boiling, or is this expected?
Known to impart off flavors if a significant amount is present in finished product
Can sometimes be seen in draw off pan / bucket as slight "oil slick"

Defoamer will float (but the boiling action probably actively mixes it)

If defoamer floats, can it be avoided in the finished product by drawing off below the syrup level?

Defoamer may boil off

Plausible means would be by "steam distillation" (What I found to be the more accurate term compared to "steam extraction")
Boiling point of defoamer by itself is much higher than water or syrup, but the mixture may reduce that boiling point

Defoamer may be filtered

Although oils can sometimes be removed from mixtures with filtration, the filter press used in maple production cannot do so



I'm currently thinking this: Defoamer does not react with the syrup and stops working only when it leaves the process. It leaves the process through evaporation and possibly draw-off. A perfect amount of defoamer would be enough to effectively reduce foam while still being completely evaporated before draw-off.

I'm interested in further thoughts! Perhaps I need to get out the old still and do some experiments.

Thanks,
Chris