Finishing Syrup/ Correcting Density - What do you do??

[michiganphil]

So I was thinking...

I take a draw off of the evaporator when it's 'almost syrup'. Once I get a couple of gallons in the drawoff pail (usually at the end of each boiling session) I finish it on the gas burner bringing it to final density.

Hydrometers work on density of the whole solution(sugar+water+anything else). Since I check density when I finish, and there is niter and 'sludge' all mixed in the solution, will the density be significantly off after filtering? Should I be checking if adjustment is needed before bottling?

I have been doing it this way for years, and never had spoiling issues in the past, but wonder if after filtering, my syrup is actually lighter density than I thought.

What is your experience??

[TunbridgeDave]

I always check density after pressing. I check it when re-canning into jugs from bulk containers also. I think the "sludge" would have a minimal effect. Why take a chance on having it spoil or having it too think and crystallizing. I must be one of the few that still finishes on the rig.

[spencer11]

It shouldn't make a difference, and if it did you wouldn't even notice it, since th hydrometer a measure density, you can't change the density of something unless you change the what it's made of

[ennismaple]

I expect the sugar sand will give a false density reading but I don't know how much it could put off the number.

We measure density after the syrup is filtered. We make sure it comes off a little thick and then thin with a bit of pre-heater condensate to get back to 66.5 to 67 Brix.

[jrgagne99]

I don't think the niter will affect the measurement, because it is not in solution like the sugar (i.e. it can be easily filtered out). Think of it as a cup of water with a bunch of sand stirred up in it. You're still just measureing the density of the water. If you prefer, think of an extreme case, like a five gallon bucket of water with hundreds of pebbles suspended in it by tiny strings. If you stick a hydrometer in there, it will still just read 0 Brix, becasue the pebbles aren't in solution. If you stir in some sugar or salt and dissolve it, then it becomes a different situation.


Also, a bit off-topic, but don't forget to lower the hydrometer into the cup to just above the point where you think it will float, then slowly release it. Hydrometers that "bob" back up to their floating position will often pick up syrup on the shaft, causing it to float lower, and give a "light" reading. The situation is worse with cold e.g. 60F syrup that is highly viscous.

[Tweegs]

When I shut down I draw off two 1 gallon jugs. Dual purpose, first, it helps me reestablish the gradient on the next start up, but more to the point of this thread, it also provides a source of “almost syrup” that I can use to cut what might be too thick. Of course, if I drew too thin, we finish on the stove and filter again.
We refrigerate overnight, let warm to room temp on bottling day and recheck density then.

A good thermometer capable of reading tenths of a degree or PID controller + RTD (both will cost about the same) can really hone in on when it is syrup. I check with the hydrometer every couple of hours and adjust my draw off temp accordingly, aiming for about .5 brix light (66.5). By the time it cools and we reheat to bottle, it will be 67.

With the digital temp reading, not much comes off thin or thick.

[PerryW]

Interesting! Never thought about the suspended nitre affecting the hydrometer reading. I suspect that the actual density of the suspended particles must be heavier than the syrup is (since it eventually sinks to the bottom of the syrup); so it would make the syrup appear heavier than it really is. But I also suspect the effect is so small that it can be ignored.

For me, I check the density several times per drawoff and run directly into the filter/canner then directly into the 5 gal drums. I always make sure I am slightly heavy so that when I reheat the syrup, I can just add water to standardize.

[michiganphil]

I don't think the niter will affect the measurement, because it is not in solution like the sugar (i.e. it can be easily filtered out). ... If you stir in some sugar or salt and dissolve it, then it becomes a different situation..

That is a good point. I hadn't thought of it that way.

I suppose that would hold true for the hot test when the syrup is less viscous, but the more it cools the stiffer it gets. If it cooled too certain point before those solids precipitated out, I would suppose they are sort of trapped 'in solution', and would make the density seem higher. Think about throwing some sand into a container of motor oil instead of water, it would most definitely make the whole sample more dense without the sand actually being dissolved.

I guess we'll have to play scientist and run an experiment...

[michiganphil]

It shouldn't make a difference, and if it did you wouldn't even notice it, since th hydrometer a measure density, you can't change the density of something unless you change the what it's made of

But when you filter, you are essentially changing what it's made of...you're removing the objectionable ingredients.

[RunInCircles]

I'm having a heck of a time getting a proper density measurement. I use a digital probe thermometer and measure boiling water temperature to get my bearings, and draw off at 7 up from that. I got a new 16x16 filter/canner this year and kept checking the hydrometer. The temperature got as high as 224 (:o) and I started to panic, so I figured it must be time to bottle. Lo and behold, it's still thin. I have never had success with a hydrometer. By that, I mean I have never gotten it to even float. Reading in here about syrup sticking to the stem was enlightening, but I can't imagine this is the issue. Is there a secret, or am I just anxious and impatient?

Perhaps the thermometer is giving a skewed reading based on contact with the base of the pan? In the evaporator or canner will the temperature be uniform enough throughout the liquid to give an accurate temperature reading?

[JoeJ]

In my opinion, your problem is the digital thermometer. I don't like digital thermometers and don't trust them. A good standard thermometer and a hydrometer is the most accurate method of checking finished syrup density. If the syrup is the correct density, it needs to be 211 degrees and the hot syrup red line on the hydrometer floats at the surface of the syrup.

[michiganphil]

So here's the update...

I had a few gallons of syrup from Monday that I needed to filter and bottle. When I got to it yesterday, it was cold.

1. I checked the temperature, made correction to hydrometer reading, and the density was right on.
2. I began to slowly heat it up, checking the temp, adjusting the hydro reading, and verifying density every so often just to make sure that I didn't need to correct it.(and I didn't)
3. Got it up over 200 so it would filter nicely, and filtered it.(cone filter)
4. By the time the filter had drained, the syrup had cooled to about 160. I again corrected the Brix reading for 160 deg, and checked density. IT WAS STILL RIGHT ON!
5. I finished taking it up around 185, and bottled.

CONCLUSION:It seems like the density will not be affected by what's removed during filtering. But, I think that I will try to get in the habit of checking the density after filtering anyway, just to ensure a quality product.

[jrgagne99]

CONCLUSION:It seems like the density will not be affected by what's removed during filtering. But, I think that I will try to get in the habit of checking the density after filtering anyway, just to ensure a quality product.

That's definitely good practice to check the density of the actual final product that you are bottling.

It seems that you have confirmed that if it's not in solution, it doesn't affect the density of the liquid, at least from the hydrometer's point of view.