Help me please: Calculating correct sugar content

[smoothlager]

I hope you can help me with some guidance: any info will be very greatly recieved.

I have just begun to make wine and so far following recipes when using my hydrometer both of the wines i have started have been 110 SG at the start which equals about 17.5 %. I would like my finished wines to be more like 14%. Can I calculate my sugar to achieve this and if so how? I presume I have to know the sugar from the fruit I use, how do i find this out?

my next planned wines are Elderberry and Pear (Any specific info on these would be good)

Any advice would be gratefully recieved, thankyou

 

[Moley]

I have just begun to make wine and so far following recipes when using my hydrometer both of the wines i have started have been 110 SG at the start which equals about 17.5 %. I would like my finished wines to be more like 14%. Can I calculate my sugar to achieve this and if so how? I presume I have to know the sugar from the fruit I use, how do i find this out?

There are very few cases where you can actually measure an OG for wines with a hydrometer.

For example, with juice wines going straight into a DJ you've got to leave headspace at the start or it will overflow. If you measure an OG but then top up with water when fermentation has quietened down, that OG is cocked up and you have to correct for volume changes. That also means that you have to calibrate some fermenters. 5 litre water bottles will hold exactly 5 litres to the base of the neck but it's useful to mark them off (sticky tapes or permanent pen) at 4, 4.25 and 4.5L. Gallon DJs are rarely exactly one gallon, they vary, I've got about 40 and can't be bothered to calibrate every single one.

If you started with 4L in a 5L bottle and later top up with water, multiply your gravity points by 4/5, for example (1.) 100 x 4 / 5 = (1.) 080

With fruit wines it can get very tricky, it might take a few days to extract all of the fruit sugars so your initial gravity reading will be too low, and then if you start fermenting on the pulp it stuffs up the maths completely.


Bear with me, I'm going to add to this topic in stages and try to turn it into a “how to” guide.

 

[Moley]

First off, let's go back to how to read a hydrometer.

Hydrometer readings are always given to three decimal places even if the last digit is a 0, so there's no such reading as 1.05, that should be 1.050

Ignore the 1. and think of 1.000 as zero, so that's 50 points

1.110 is 110 points, 1.036 is 36 points and 0.995 is 5 points below zero.

36 points is an important one, because 100g of sugar in 1 litre gives 36 points.

If you buy fruit juices, the sugar content is printed on the carton, so let us consider a Wurzel's Orange.

One litre of white grape juice might contain 150g of sugar, one litre of orange juice might contain 100g of sugar, you might add 850g of granulated sugar and ultimately end up with a 5 litre brew.

150 + 100 + 850 = 1100g sugar in 5 litres = 220g / litre

100g / litre gives 36 points, so 220g gives 2.2 x 36 = 79 points. Your OG is 1.079

If you started that at 4 litres your hydrometer would say 1.099, which is why I said you have to adjust for volume changes if you add more water later on.

If you want an OG of 1.090, work it backwards:

90 / 36 = 2.5 so you need 2.5 x 100 = 250g sugar per litre x 5 litres = 1250g, and there is 250g in the juices so you need to add 1000g.


I'll be back later to talk about real fruits, but for smoothlager's reference, elderberries have an 11.5% sugar content and pears are 10%.

 

[smoothlager]

After I posted i had a think about this and roughly calculated that the original 17% may be about 15 once I had added water but very rough estimate and then it all got messed up when I considered fermenting on the pulp. I will mark my demijohns though this is an excellent idea and will help me get closer to my goal
Thanks

 

[Moley]

If you are using fresh fruits, the same principles apply, but you need to be able to calculate the sugar content of the fruit. There are various tables around on the web but these are a few examples I've collected. For dried fruits, read the packet.

Apple (Cooking) 9%
Apple (Eating) 12%
Apricot 8%
Banana 17%
Blackberry 7%
Blackcurrant 8%
Blueberry 8%
Bilberry 6%
Cherry 12%
Cranberry 4%
Damson 9%
Elderberry 11.5%
Gooseberry 8%
Grape 15-20%
Grapefruit 6%
Greengage 11%
Guava 7%
Hawthornberry 8%
Kiwi 14%
Loganberry 5%
Lychee 17%
Mango 11%
Medlar 11%
Orange 11%
Papaya 8%
Passion Fruit 8%
Peach 9%
Pear 10%
Pineapple 13%
Plum 10%
Pomegranate 13%
Raspberry 7%
Redcurrant 6%
Strawberry 6%
Tangerine 7.5%
Whitecurrant 5.5%
Lemon, Lime, Rhubarb - too low to bother about.

Digressing for a moment, when calculating alcohol by volume you divide the gravity points dropped by a factor. I learned that to be 7.36, others use 7.46 so to avoid argument I'm going to split the difference and call it 7.4

So for example, you are making 5 litres and using 1kg blackberries + 500g elderberries

You want a wine of 14% abv so you're looking for a gravity drop of 14 x 7.4 = 104 points

Most wines will finish around 0.990 (10 points below zero) so we want an OG around 1.095

95 / 36 x 100 = 264g sugar required to the litre, x 5 = 1320g total.

1000g blackberries x 7% = 70g sugar
500g elderberries x 11.5% = 58g sugar

70 + 58 = 128g and I usually guestimate on 90% extraction = 115g sugars from fruit.

1320 - 115 = 1.2kg to add.
Simple :thumb:

 

[smoothlager]

Digressing for a moment, when calculating alcohol by volume you divide the gravity points dropped by a factor. I learned that to be 7.36, others use 7.46 so to avoid argument I'm going to split the difference and call it 7.4

So for example, you are making 5 litres and using 1kg blackberries + 500g elderberries

You want a wine of 14% abv so you're looking for a gravity drop of 14 x 7.4 = 104 points

Most wines will finish around 0.990 (10 points below zero) so we want an OG around 1.095

95 / 36 x 100 = 264g sugar required to the litre, x 5 = 1320g total.

1000g blackberries x 7% = 70g sugar
500g elderberries x 11.5% = 58g sugar

70 + 58 = 128g and I usually guestimate on 90% extraction = 115g sugars from fruit.

1320 - 115 = 1.2kg to add.
Simple :thumb:

This is a great help and I will use this and the other info when I make my next wines, thanks

 

[shearclass]

because 100g of sugar in 1 litre gives 36 points.

I have finally got my head around these reasonably simple sugar calcs, and have created a spreadsheet to work it all out for me in future.

However, one question remains, when you say 100g sugar in 1 litre, does this mean

add 100g sugar to 1 litre water, ending up with more than 1 litre of solution

or

1 litre of sugar water solution

Cheers

 

[BeerEagle]

Picky! :lol:

 

[Moley]

when you say 100g sugar in 1 litre, does this mean add 100g sugar to 1 litre water, ending up with more than 1 litre of solution, or 1 litre of sugar water solution?

The latter :thumb:

If you add 100g of sugar to 1 litre of water you will end up with approx. 1060ml of solution @ 1.034

 

[shearclass]

Excellent Moley, as always.

Cheers

 

[oldbloke]

because 100g of sugar in 1 litre gives 36 points.

I have finally got my head around these reasonably simple sugar calcs, and have created a spreadsheet to work it all out for me in future.

Cheers

You might want to add a bit to that spreadsheet to cope with losses when racking
Musing on it t'other day and having a quick fiddle in Excel I found that if you want to end up with say 13% and you rack twice, you want to start off with about 15%-worth of sugar, depending how much you lose and top-up each racking.

 

[shearclass]

Well i figured i could approximate the ABV by measuring how much liquid i have to start with (hence question above, is it liquid with or without sugar) and then by measuring how much water i use to top up after racking, i could then adjust the abv accordingly.

I assume that is what you are referring to? Racking wouldn't lower the abv, but topping up would. Or have i missed something?

 

[alanywiseman.]

You are correct. It is the topping up that lowers the abv. If you were a bit pedantic you could top up with the correct concentration of sugar solution.

 

[shearclass]

If you were a bit pedantic you could top up with the correct concentration of sugar solution.

Nah!

If I have mroe than a demi full when i rack from fv, then i tend to keep the surplus in a litre bottle and use that to top up with, but otherwise, water will do.

 

[Laurin]

I found this calculator really helpfull if I need to calculate how many sugar I need to add or what my potential ABV is.

 

[yellafella]

Sorry if its been posted before but this applet seem very useful, especially the Sugar bit which allows you to tell it OG of a starting volume and you say what finishing volume you need and it tells you how much sugar to add and water.

http://web2.airmail.net/sgross/fermcalc ... pplet.html

 

[shearclass]

I usually guestimate on 90% extraction

Where does this theory come from? I always wonder if a lot of the sugar is left behind when straining is done, including some of the extra sugar that is added.

 

[Moley]

Where does this theory come from? I always wonder if a lot of the sugar is left behind when straining is done, including some of the extra sugar that is added.

If you want a definitive answer then David is the expert, he visits THBF occasionally but lives on the Harris forum.

You are right though, that some sugar is likely to get discarded in the spent fruit pulp, but I have merely tried to take an educated guess at the amount from SG at the time of straining and weight of pulp discarded after pressing.

However, I don't add much of my sugar until after straining, so when I do strain the gravity is likely to be around 1.000

For example, with a 5 gallon must I mighty throw in 1kg of extra sugar at the start but I won't give those yeasties more than they can handle in that first few days.

 

[Dave Ne]

i dont use my hydrometer any more as most of my brews are concentrated at the start, then when the brew has settled they are topped up with water. I have found a great number on another forum though, (1078g) of sugar per gallon will give 12 1/2% alcohol, so that No combined with Moleys chart is good enough for me, Dave