My question is about hydrometer readings in country wine. I've been using the various recipes but now want to move on a little. I want to be able to take my readings and add the right amounts of sugar based on the sugar in the fruit. The problem I have here is that when you use fruit, won't the fruit itself throw off the readings? Won't the added mass of the pulp change the SG? Thanks.
Greg
I am new to wine making, but I will give this a shot:
No, it shouldn't. In all the fresh-fruit recipes that I have read, they all say to put your boiling water and other ingredients (save yeast and sugar) over your fruit and then let it sit for a day before taking your measurement and adding sugar.
The purpose of this waiting time is to give the water time to permeate and dissove out any sugar (and other flavor-enhancing chemicals) from the fruit. As long as the floating bits and pieces do not interfere with your hydrometer or not allow you to read it, they should not affect the reading.
Imagine this: you have a glass of distilled water that reads 1.000 on your hydrometer. If you drop a piece of glass into the water, will the reading change? Nothing dissoved. No temperature changed. The reading should not change.
Now imagine that you put a sponge in the water. Same thing, nothing dissoves. No temperature changed. The sponge did absorbe a little water, but not amount large enought to affect the overall level of the water. The reading is still at 1.000.
Same thing with fruit. When you first put your water over it, all kinds of things dissolve out. After the initial time period, nothing else dissolves out. I can see with some types of fruit, you may need to wait longer than a day for everything to equalize before you measure and add sugar. Just take a measure ment every few hours and wait until the reading does not change. I bet that the obligitory 24 hours is enought for most if not all standard fruit.
Hope this helps,
Alex.
Not to disagree, because you really did an excellent job of explaining why one should NOT worry too much about the effects of solids in the must while taking SG measurements, but the fact is that it does have an effect. If the solids are suspended in the water (not like your marble which drops right to the bottom).
Non-soluble Solids increase the measured SG of the fluid some. Due to things like skin effect and rafting, significant chunks of fruit (i.e. big enough to push around with your finger), can grab hold of your hydrometer and help lift it a little higher. All in all the effect is not too drastic, but it can effect your reading by way of falsely "lightening" the measured specific gravity by up to 0.020 (that's conjecture, I don't have solid references). You can see the noticible difference yourself if you take the time to draw off some of the clearer / chunky free must and remeasure. You will find your reading is in fact different. Again though, its generally not enough to worry about. If you followed your recipe well, you'll do just fine. Its more an issue for people that are really concerned exact content of the must throughout the life of the fermentation and subsequent wine.
Good point Scot. Another effect is if the fruit in the mix has a positive buoyancy as with the cap rising. Then it can help lift the hydrometer and cause it to read too great of an SG. Once again, this effect can be avoided by straining out the large pieces and doing your measurement on juice only.
However, there is another effect and that is sugar that is bound in the fruit must and not dissolved in the juice. The yeast will find this sugar and eat it during fermentation but the hydrometer will not see it when you do your early measurement.
I think you just have to realize that SG is a guide to the potential alcohol but it does not give a precise measure. It is not that important. Just enjoy your wine.
Ray
This is what I was getting at. I want to be at least in the ball park. I know that many of the recipes shoot for about 1.095 or so. If I'm ONLY measuring the sugar that I added, then I'm certainly going to have a much sweeter wine than I planned. I do taste each racking and try to adjust a bit.
As another way of looking at this, if I use 4 pounds of fruit per gallon, (that seems to be about average for fruit) what's a good rule of thumb for sugar added?
Greg
If your fruit is raisins then 50% by weight. If you are talking sour wild plums I would bet it is considerably less than that. (Like negligible.) I would love to see a table of sugar content of different fruit. It would be very helpful. But without it, it is just a judgment call and an inexact science.
Ray
I had not run across that before. It is useful info.
Ray
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