Very high niter, low BP

[berkshires]

I had a strange experience I thought I'd share with you fellow mapletraders. Maybe it's something some of you have seen before. Basically it was a batch with super-high niter, and this seems to have caused the boiling point to lower. Here's the back story:

I have been using a cone filter, and after each time I filter and bottle, I stick the filter in the freezer. Then next time I boil, I toss it in the hot sap to get all the syrup out of the orlon filter and into the next batch (but not the pre-filters, that have most of the niter in them). So I did my final boil of the season and filtered and bottled over the weekend. That left me with a few pre-filters and an orlon filter with a fair amount of syrup in them, and no more boils. So I tossed them in a pot with a little water to get the sugar out. Then I let it sit to cool down, and poured off the syrup-water, leaving a lot of niter behind. I then cooked that sugar-water down into a little micro-batch, that I figured I'd just leave in the fridge for a month or so to settle out naturally for my own personal use.

Okay so far so good. Here comes the weird part. Normally I use a thermometer to get close, and then use a hydrometer at the end. But this time when I got to 217, the pot started foaming up a lot (little tiny bubbles, like when it's getting to syrup). I figured this was because there was a ton of niter in this batch. It was kind of a pain to deal with, but I didn't think anything more about it. Then when it got to 219 I measured it in the hydrometer. Now normally when I first get to 219 I'm one or two brix down from syrup, and I just keep testing until I get there. But this time my first measurement I was about three or four brix over! I couldn't believe it, so I kept checking - no doubt about it, I was way over syrup at 219. I had just finished my regular batch, which finished as normal at around 219.5. So the only explanation was that all the extra niter had suppressed the boil temperature. I went ahead and added distilled water until I got it down to syrup.

Has anyone else ever seen this?

Gabe

[tcross]

I had that problem last Friday evening. I had a substantial amount of nitre build up. it looked like syrup, sheathed like syrup but wouldn't read correct on the hydrometer. so we kept boiling and checking. before we knew it we were 3-4 brix high and drew off and added sap like crazy to avoid a big problem. I assumed all the syrup was being held back by the nitre and bubbles... but I can't be sure. never really had that happen before. at least not to that extent.

[DrTimPerkins]

Has anyone else ever seen this?

Excessive foaming can cause erroneous temperature readings. Niter might have been what contributed to the foaming though.

[blissville maples]

Also have had weird temp experiences....Syrup sheets all the way across but only 218.....I try to go by sheeting, as I feel that never changes. I find very light sheets that come after holding Dipper for a couple seconds start at 63-65 brix(use refractometer). And syrup falling off in heavy sheets instantly is 70+, when Dipper shows me a good solid sheet instant, but not falling off in sheets it's 66-68 right on q.

[DrTimPerkins]

Syrup sheets all the way across but only 218.....

My early recollections are that my grandfather, father, and uncle used the sheeting method and temperature mostly. It is fairly reliable once you are familiar with it. I can't recall seeing a hydrometer in the sugarhouse, but perhaps I just wasn't paying any attention.

[Homestead Maple]

My first draw last night was at 218.8 and two hydrometers read the same. The last hour of boiling syrup it was coming off at 221.4 and again I checked the density with two hydrometers. I've never seen that much of a temperature difference in one period of boiling. Maybe niter had something to do with this, which could have been caused the quick warm up in temperatures yesterday.