SG

[Rappatuz]

So I've worked quite hard this summer picking wild strawberries to make a super delicious wine (hopefully). Two days ago I took 3.6 kg of berries out of the freezer, put them in a fermenting bucket, added tartaric acid, sulfite and some water, before adding pectic enzyme half a day later. All good (divine smell).

Yesterday, I calculated how much sugar I would need to get 11 % abv for the target volume; eight liters. (214 g/l)*(8 l) = 1712 g sugar. According to several online sources strawberries contain about 5 % sugar. 3.6 kg should add about 180 g of sugar to the must, which means that I needed to add ~1530 g of sugar, which I did. Then I measured the OG, which should've been around 1.085. Somehow it was in the territory of 1.115/300 g/l (actually off the charts on the hydrometer). The volume is just about eight liters. This just doesn't make any sense. Help?

I want to point out that I'm sure my sugar additions were correct (I measured carefully before adding). The sample I tested had a fair amount of floating sediments. Could that throw off the reading to this extent?

 

[cmason1957]

Floating sediment certainly will throw off the reading and make it much higher. One other thing to keep in mind, your strawberries weren't 5% sugar. They are always more or less sugar than average. Unless you are very lucky.

 

[Johnd]

@cmason1957 is right. Best to thoroughly mash / mix your must to make sure the berries are crushed and the sugar is dissolved. Sanitize and sink a strainer into the must, just enough for clean juice to flow into the strainer, scoop some out to fill your hydrometer test vessel, and check your SG. If all is sanitized, you can dump the juice back in. Of course, if you have a refractometer, a couple drops will do the trick. Online sources are fine for rough estimates, but your fruit has the readings you need.

 

[Rappatuz]

Floating sediment certainly will throw off the reading and make it much higher. One other thing to keep in mind, your strawberries weren't 5% sugar. They are always more or less sugar than average. Unless you are very lucky.

Of course the sugar content isn't exactly 5 %, but it should be somewhere close to it. Lets exaggerate and say the content is 10 %. Then the total sugar amount would be about 1890 g. This equals to 236 g/l, an SG of 1.090, and about 12.2 % potential ABV, which is far lower than what I measured. I guess the lesson learned is to filter the sample before measuring SG.

@cmason1957 is right. Best to thoroughly mash / mix your must to make sure the berries are crushed and the sugar is dissolved. Sanitize and sink a strainer into the must, just enough for clean juice to flow into the strainer, scoop some out to fill your hydrometer test vessel, and check your SG. If all is sanitized, you can dump the juice back in. Of course, if you have a refractometer, a couple drops will do the trick. Online sources are fine for rough estimates, but your fruit has the readings you need.

Second lesson learned would be to measure the must before adding any sugar.

I have a theory that could explain the offset: Could the fact that the must contains a mash of not-totally-dissolved berries (which partly makes out the eight liter volume) make the sugar more concentrated in the "liquid part" of the must? Could that be it?

Thanks guys!

 

[Johnd]

I have a theory that could explain the offset: Could the fact that the must contains a mash of not-totally-dissolved berries (which partly makes out the eight liter volume) make the sugar more concentrated in the "liquid part" of the must? Could that be it?

Thanks guys!

It could be that all of the juice hasn't been released yet, since your fruit was frozen, thawed, and mostly mashed up, I wouldn't suspect that it would be substantial. A day with some pectic enzyme onboard would certainly help. You'll want to use a good bit of pectic enzyme anyway, as strawberry is high in pectin, and it'll help it clear later in the process.

 

[Scooter68]

VERY TOUGH to get a real reliable SG reading with loose ,(floating).fruit in a bucket. Either draw off a sample into a testing tube or find a way to keep the fruit flotsam away from the hydrometer and that means away from the bottom too.

And yes, SG measurements before adding any sugar is the safest route. After a few batches of fruit from the same source you can get a feel for what to expect, but with fresh fruit variations can be pretty wild, especially if wild sourced with weather variations.

 

[stickman]

I agree with the above comments, but it seems like even after measuring the initial SG, you still have to estimate the net liquid volume before doing any calculations for a sugar addition. I wouldn't think you would use the 8L total must volume for calculations, should be something less than that. Even so, you know the standard rule applies, "add half of what you calculate then check results".

 

[Scooter68]

Then there is that nebulous adjustment to make for volume loss. I don't top up with wine. I use water or saved "extra wine from that batch that has been stored in smaller glass bottles under airlock. By always going in a little heavier on starting volume, fruit/gallon, and slightly higher ABV I don't feel the need to worry about adding 8-12 oz of water to a 3 gallon batch. The flavor isn't going to be hurt if I plan for it. Example would be a peach wine where the only water added at the start is to make my simple syrup (2:1).

 

[Rappatuz]

I agree with the above comments, but it seems like even after measuring the initial SG, you still have to estimate the net liquid volume before doing any calculations for a sugar addition. I wouldn't think you would use the 8L total must volume for calculations, should be something less than that. Even so, you know the standard rule applies, "add half of what you calculate then check results".

I have a nylon bag covering the inside walls and bottom of the fermenting bucket. It is kept in place by hanging it over the outer walls of the bucket. It contains about 95 % of the pulp (a tiny bit manages to get through the fine mesh). When I lift it up the volume in the bucket is halved. While holding it up, liquid keeps seeping out of the bag, but very slowly. Although a lot of liquid is trapped in the pulp, I don't think the total liquid can be 8 liters. I would guess that the real volume of the total liquid is somewhere around 6-7 liters. The reason the SG was so high was probably due to lower liquid volume than estimated, and floating sediments in the test tube.

Then there is that nebulous adjustment to make for volume loss. I don't top up with wine. I use water or saved "extra wine from that batch that has been stored in smaller glass bottles under airlock. By always going in a little heavier on starting volume, fruit/gallon, and slightly higher ABV I don't feel the need to worry about adding 8-12 oz of water to a 3 gallon batch. The flavor isn't going to be hurt if I plan for it. Example would be a peach wine where the only water added at the start is to make my simple syrup (2:1).

My philosophy is to use the "right" amount of fruit to make the wine as flavorful as I want it. That goes for target ABV too. I calculate how much I need of each ingredient per liter (including sugar), then I make a little bit more than what I want to end up with. Lately, my batches have all been in the 5-7 liter target range. Typically, I expect to lose a liter in the process, so I would start out with 6-8 liters.

 

[DoctorCAD]

Hydrometers measure EVERYTHING in the must, sugar, pulp, seeds, cat fur, flies, shoe dirt etc.
Try to get a sample strained through cheese cloth and measure that. It should be closer to a true sugar SG.

 

[Rappatuz]

Hydrometers measure EVERYTHING in the must, sugar, pulp, seeds, cat fur, flies, shoe dirt etc.
Try to get a sample strained through cheese cloth and measure that. It should be closer to a true sugar SG.

I agree that all of those examples would be measured by a hydrometer. I don't think a shoe sole would be registered, though. Or a magnet. But I agree with you and think it will be a good idea to filer samples in the future. I took my sample from "outside" the nylon bag, but some minor strawberry parts had lured their way out of it. One lesson I have learned. Nylon bars won't keep wild strawberries at bay. They're just too wild for that!

 

[Scooter68]

In the measurement of the SG for me I just use basic practices but not going to extremes of super filtering or others measures to get juice to test the SG.

For best accuracy crush fruit well and do sugar additions as simple syrups at least a day before taking a "final" measurement. Same for acid adjustments. ( Those are less problematic as I just want the pH in a range of 3.4-3.6). Just adding undissolved sugar directly to the must runs the risk of an SG reading not reflecting undissolved sugar. (Even if you stir until your arm falls off) That can yield a higher than expected/desired ABV or a ferment that stalls out ends before all sugars are converted because conditions exceed the yeast's abilities.

Since i only work in fruit wines - fresh fruit takes a day or two (or longer) to break down enough for the sugars to register properly in the SG. Juice only fruit wines are much easier in that way.

 

[Rappatuz]

In the measurement of the SG for me I just use basic practices but not going to extremes of super filtering or others measures to get juice to test the SG.

For best accuracy crush fruit well and do sugar additions as simple syrups at least a day before taking a "final" measurement. Same for acid adjustments. ( Those are less problematic as I just want the pH in a range of 3.4-3.6). Just adding undissolved sugar directly to the must runs the risk of an SG reading not reflecting undissolved sugar. (Even if you stir until your arm falls off) That can yield a higher than expected/desired ABV or a ferment that stalls out ends before all sugars are converted because conditions exceed the yeast's abilities.

Since i only work in fruit wines - fresh fruit takes a day or two (or longer) to break down enough for the sugars to register properly in the SG. Juice only fruit wines are much easier in that way.

I do make simple syrup before adding it to the must. A lesson learned is to not add the estimated sugar amount all at once, but split it into two or more additions. Also, filtering will make me more confident that I actually can trust the sample.