Determining SG of plum wine must

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Sep 3, 2016
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Hi all,

I've made a lot of cider and now want to make some plum wine. But I'm confused about the process. Here are a few simple questions that would really help me. I now have a tonne of plums. (Actually, more than a tonne...)

1. I don't understand how to take the SG (or brix, or however you want to measure sugar content). I've removed pits and crushed the plums. It's now a thick stew of plums, in a 200L (or 250 gallon) barrel. Surely, one can't just add SO2, or pectin enzyme, etc, to this stew. It would just sit on the top. So, I should add water and mix it up. and then add these. Right?

2. But, I'd like to know how much water to add in order to get the right SG! How do I measure that? I could add some water and stir, and then pull some of the water/plum mixture out with a wine thief to test the SG (provided the plum doesn't plug up the opening of the wine thief). But the problem here is that the plum won't have released its sugars into the water sufficiently to give a correct reading. So, again, how does one take the SG?

3. One possibility would be to strain some of the plum juice out of the plum puree into a hydrometer tube, and test it that way. Is this the correct method?

4. If that's the correct method, then should I add water to the strained plum juice until the SG is where I want, and use THAT as my guide as to how much water to add to my barrel?

5. But, the problem here is that I have no way of knowing how much plum juice there is in the barrel of plum puree.

So, as you can see, I'm at a total loss about how to get started. Apples are so much easier, because you just deal with the juice...

Thanks for your help!!



Senior Member
Jun 1, 2016
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Regarding the pectic enzyme, add it on top and then use a paddle to mix it in. After a day, it'll all be mush, then you can take a strainer and measure the SG.
Most people on here will tell you to NEVER add water to your must.
Good luck!!!


Just a Member
Aug 19, 2012
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My advice, FWIW:

1. Yes, mix it in.
2. Not sure how water became so evil around here. There is not automatically anything wrong with adding a little water. Lots of good wine has been made with the addition of some water. I just depends what you are after.
3. Yes, strain off some liquid, this is what you check your SG on.
4. In all likelihood you will not be adding water to get the SG down. You will likely be adding sugar to get the SG up.
5. That is a problem sometimes. I've made some high-pulp wines like persimmon where paradoxically, more fruit yielded less wine because of the gross lees losses.


Fruit "Wine" Maker
Aug 29, 2015
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Northwest Arkansas
Agree totally - Water is not the enemy to a wine. Especially to that much fruit.
And in this case making a simple syrup (2 parts sugar to 1 part hot water - then cool before adding) that will add a minimum amount of water to get the SG up.

Stressbaby has it spot on.


Super Moderator
Super Moderator
Dec 4, 2009
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There are certain fruits you don't want to add water to, such as plum, peaches and apples. Blackberry and elderberry can use water without affecting the flavor.

Yes you could add water but remember you are weakening the flavor. Once you make a plum wine without adding any water you will understand.

If you push a strainer down into the must you can pull off enough juice to take a hydrometer reading.

I would pull some juice off of you must and add sugar to that, heat it up until sugar is dissolved.

1 cup of sugar will raise sg approx. .018 per gallon.
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