Evaporation rate in morning versus afternoon

[gatzow]

Question for our scientists in the group. I am running a 2x4 Corsair with PRo pan in a little 12x14 shack with Coppola. I find that my evaporation rate in the morning is 15 gph but in the afternoons it’s slows to a crawl. Usually in the range of 7gph. I fight to make progress. I was curious what factors all come into play. Is my shack just that filled with moisture that when paired with afternoon temps it just fights to boil off? Is my confined little shack with minimal air flow a part of the problem? Am I just tired after a long day and not adding wood like I am in the morning - ie - am I crazy and this has nothing to do with anything other than me?

Curious what the science is behind this if anything.

Thanks

[ecolbeck]

I doubt the shack or weather have anything to do with it. Are you using a blower? What is your wood situation? One idea is that without a blower and using hardwood fuel your grates are filling up with coals and blocking airflow. This would slow the fire down.

[gatzow]

I have a blower but I have been trying to pay closer attention to grates. It definitely caused problems in one boil when adding too much wood over long periods. Most wood is elm and oak.

[ecolbeck]

How often are you adding wood?

[gatzow]

2 pieces every ~7 minutes. But that does vary based on size and type of wood. I’m trying the less is more model to keep the fire box cleaner. And I wasn’t using the blower consistently because as the propan gets “sweetened” I was having more and more bubble issues. Still learning this setup as to how to run it the best. Including doing a couple full clean outs a season so I can clean niter out of the finish pan and when new sap is in, lots less bubble issues then when there is 5 gallons of syruo sitting in pan.

[ecolbeck]

Are you saying that you're slowing down the fire in order to keep foaming in the syrup pan under control? Are you using a defoamer? 2 pieces of wood every 7 min doesn't sound like much wood. How big are the pieces?

[gatzow]

I have been in situations where I have to open the fire box to stop the foam - yes. I am still learning how much wood I can add to keep a good rolling boil without foam.

Do I use defoamer - I have the “cup” that Smokey lake offers to put some oil in to help stop foam - but I’m hesitant in using it as I used too much last year to control foaming and I just don’t want to have to do that this year. I am not applying defoamer to my pan that others sell.

I’m assuming deformed would really let me hammer the fire and the boil to help speed, I guess I’ve just stayed away from it as I don’t know much about it and all the back and forth in reading of people that are for/against adding anything to their syrup.... all the arguments have kind of scared me away from it...

[ecolbeck]

Overuse of defoamer can affect syrup. Im not sure how much is too much. It is my understanding that commercial defoamers work better than vegetable oil. The instructions on the CDL defoamer I use say to use it only when the foam threatens to flow over the sides of the pan, presumably to limit overuse.

[gatzow]

Yes. Last year I had a boil or two where I used to much. I literally had a couple bottles where I could see a drop of oil in my finished syrup - and that’s after all filtering, etc. I have a 16x16 flat filter and all that good stuff - so I knew I made a mistake and had to back off, but that has also made me nervous. I bought the cup hoping that it would stay in the cup if needed/used and would then stay out of the sap completely, but again, after last years mistake, I’ve been reserved to use it.
I’m only about 10 boils into the new setup and still learning. I’ll really watch the grates today/tomorrow and make certain it’s clean. I’ll still potentially have foam issues if not using a tool to help, but I guess that’s on me to choose and know what the consequences are. Hopefully as I keep learning about wood, I can find that happy place where I keep a great boil going without creating too much heat that causes the foam... appreciate the conversation.

[ecolbeck]

Best of luck to you. Sounds like you’ve made progress. Judicious use of defoamer will allow you to keep the fire hot. The blower should keep the grates open for you. Keep the wood wrist sized and fire consistently to maintain a gradient. Take advantage of that great rig you have and make some serious syrup!

[maple flats]

My best results back when I had a 2x3 pan, no flue pan was if I added 1 drop of commercial defoamer every second fueling. I fueled every 7 minutes. That way the foaming stayed in check and I could continue to make it boil as hard as I could get. The issue I had that first year was that most of my wood was a little bigger than wrist size and not knowing any better I didn't split it smaller. That changed the next year.

[DrTimPerkins]

Don't hesitate to use defoamer. This will cut back on the foam and help increase your evaporation rate. If you're not organic, then a very small amount of Karcher or Atmos will suffice. It is mostly organic producers who have issues with defoamer off-flavor, which occurs because the organic oils are far less effective than conventional defoamers.

Sounds like your fire may not be getting enough air after a while.

[Sugarmaker]

If my boiling rate dropped 50% in a couple hours I would be concerned. If any thing it should improve the later not earlier in the process. Should be at its peak when your ready to shut down for the day? Set a timer to fire at the same interval. Not sure how big your evaporator is. but if it can do 15 in the morning it should do 15 all day long.
Yes a little defomer may be needed. Just a drop at the draw off area and a drop at the hot sap inlet into the pan is all you need every time after you fire the rig. slowing down for foam is not a good thing to keep your process moving along.
Two pieces of wood each firing doesn't sound like enough?
Regards,

[maple flats]

My most recent bottle of Atmos says on the label that it is approved for Organic, I never saw that statement in the past.