How much sugar changes gravity reading? (PHOTO ATTACHED)

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CV_Apple_Gal

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I pressed my cider today and it looks like my reading is around 1046 which is a little low in my opinion. I’ve heard that less than 1045 is dangerous and I’d prefer to be farther away from that than I am right now.

I added 2lb of white sugar to my 5lb carboy. Then I did a reading and it said 1054. Does that jump seem right? Seems a little high now for the amount I added.
Is there a way to calculate the approximate gravity shift based on how much sugar was added?
Thanks!
 

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bernardsmith

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Hard to imagine why an SG of 1.045 is "dangerous". That figure suggests a potential ABV of close to 6%. Most store bought beers are about 3-4%. Dangerous? Only if you drink too much. At 6% ABV the cider won't have an enormous shelf life but ciders are about that gravity and pressed apples typically contain the equivalent of about 1 lb of sugar in every gallon of expressed juice so your juice is right on the money.

As to how much adding 2 lbs of sugar to your 5 gallons (is it?) of apple juice. (That it is IN a 5 gallon carboy only suggests the maximum volume. It COULD be 1 gallon, but let me assume we are talking about approximately 5 gallons. Two pounds of sugar will increase the gravity of water to make 1 gallon (so this is LESS than 1 US gallon of water: the TOTAL volume of water PLUS sugar = 1 gallon) by 1.090* so if we divide that by 5 (because we are diluting that gravity by 5 ) we get about 18 points (or 1.018) you added to the apple juice. If you started with 1.045 and you added .018 then your total is about 1.063. but remember my assumption is that the TOTAL volume is NOW 5 gallons.. so your figure is a wee bit low but it's close enough to the ball park if we accept tolerance for the volume, for the weight of the sugar, for good mixing etc. But if your 5 gallon carboy was full BEFORE you added any sugar It would contain MORE than 5 gallons. Five gallon carboys are LARGER than 5 gallons. They safely contain 5 gallons at about the height of the neck and not the mouth.

* Sugar in water effect on specific gravity? - Homebrewing Stack Exchange
 
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Chalkyt

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Have a look at the Vinolab Calculator (via Google). This shows your SG of 1.046 has 120g/L of sugar and your SG of 1.054 has 140g/L of sugar. So, adding 2 lbs (900g) of sugar should cause this change if added to 45 litres of the 1.046 cider.

I typically work in metric units so I have tried to replicate the above in Imperial/American units. So, if I haven't mucked up the conversion, the following shows that (using the rough "rule of thumb" that 5g or a teaspoon of sugar per litre raises SG by 0.002), approximately 2/3 oz of sugar per gallon will get your SG change of 0.008. So your 2 lbs of sugar needs about 12 gallons(45 litres) of cider to be consistent with your measured SG results.

Not sure what size your carboy is (is 5 lb a typo? If the carboy is say, 5 gallons then the numbers seem a bit out of whack) but do the arithmetic to see if this sounds about right.

Hope this helps... I just noticed that you received another reply just before I sent this one. So digest them both and see where it takes you. Cheers!
 
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Chalkyt

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I have been pondering about your question regarding gravity shift when adding sugar (i.e. chaptalization) and after a bit of research I think that your numbers are probably O.K. and not out of whack as I suggested earlier.

Having said that, if you want to know why, the following bit in italics goes into the details. This explanation gets a little heavy but stick with it. Hopefully it doesn’t hurt your head hurt too much.

Claude Jolicoeur has an interesting take on chaptalization in his book (The New Cider Maker’s Handbook), He includes a table for apple juice at different SG’s showing the mass, total solids, sugar concentration, average potential alcohol etc as well as the potential variation in some of these. The table is a compilation of published data from various sources.

Jolicoeur points out that we routinely use specific gravity (or density) as a convenient proxy for the amount of fermentable sugar in apple juice. But this isn’t completely accurate as the sugar is responsible for less than100% of the measured SG because there are non-fermentable compounds like tannins, acids, etc which also contribute to the density of the juice. For different apples the sugar content of the juice can vary by as much as 10%.

Of course, as Craft Cidermakers we aren’t easily able to measure the actual sugar content, so as a “rule of thumb” we work with what the average figures might be. For our purposes this is fine.

So, although your juice with a measured SG of 1.046 might have the average sugar content for this SG of just under 100g/L, it could really be anything from 90 to 110 g/L depending on the type and condition of the apples. By adding 2 lbs of sugar to 5 gallons of juice (i.e. around 50g/L) you could therefore end up with between 140 and 160 g/L of fermentable sugar, plus the non-fermentable solids that affect the hydrometer SG.

Just to complicate life, adding the sugar also increases the volume and mass of your cider, so the 5 gallons is now a bit more than 5 gallons and weighs 2 lbs more than it did before. A litre of your juice might now have a mass of around 1100g compared with around 1050g before the sugar was added.

So now for the arithmetic. The percent of fermentable sugar (or Brix) can therefore be somewhere between 140g of sugar/1100g of juice (12.7%) and 160g of sugar/1100g of juice (14.5%). The resulting SG range for these Brix figures from Jolicoeur’s table is 1.051 to 1.059 so your measured 1.054 is more or less right in the middle. Another “rough rule of thumb” is that °Bx=°SG/4, so you don’t really even need the table.

Time to all calm down and enjoy the resulting 6.9% ABV cider.

Cheers!
 
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CV_Apple_Gal

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I have been pondering about your question regarding gravity shift when adding sugar (i.e. chaptalization) and after a bit of research I think that your numbers are probably O.K. and not out of whack as I suggested earlier.

Having said that, if you want to know why, the following bit in italics goes into the details. This explanation gets a little heavy but stick with it. Hopefully it doesn’t hurt your head hurt too much.

Claude Jolicoeur has an interesting take on chaptalization in his book (The New Cider Maker’s Handbook), He includes a table for apple juice at different SG’s showing the mass, total solids, sugar concentration, average potential alcohol etc as well as the potential variation in some of these. The table is a compilation of published data from various sources.

Jolicoeur points out that we routinely use specific gravity (or density) as a convenient proxy for the amount of fermentable sugar in apple juice. But this isn’t completely accurate as the sugar is responsible for less than100% of the measured SG because there are non-fermentable compounds like tannins, acids, etc which also contribute to the density of the juice. For different apples the sugar content of the juice can vary by as much as 10%.

Of course, as Craft Cidermakers we aren’t easily able to measure the actual sugar content, so as a “rule of thumb” we work with what the average figures might be. For our purposes this is fine.

So, although your juice with a measured SG of 1.046 might have the average sugar content for this SG of just under 100g/L, it could really be anything from 90 to 110 g/L depending on the type and condition of the apples. By adding 2 lbs of sugar to 5 gallons of juice (i.e. around 50g/L) you could therefore end up with between 140 and 160 g/L of fermentable sugar, plus the non-fermentable solids that affect the hydrometer SG.

Just to complicate life, adding the sugar also increases the volume and mass of your cider, so the 5 gallons is now a bit more than 5 gallons and weighs 2 lbs more than it did before. A litre of your juice might now have a mass of around 1100g compared with around 1050g before the sugar was added.

So now for the arithmetic. The percent of fermentable sugar (or Brix) can therefore be somewhere between 140g of sugar/1100g of juice (12.7%) and 160g of sugar/1100g of juice (14.5%). The resulting SG range for these Brix figures from Jolicoeur’s table is 1.051 to 1.059 so your measured 1.054 is more or less right in the middle. Another “rough rule of thumb” is that °Bx=°SG/4, so you don’t really even need the table.


Time to all calm down and enjoy the resulting 6.9% ABV cider.

Cheers!
Thank you for following up!
I agree now as well, my numbers don't seem that off. And I used a tilt that basically confirmed my numbers. Thanks for the info!
 
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I've read the explanations above, and they are fine, but a simple estimation is that 1 lb of sugar in 5 gallons will add about 8 gravity points. 2lb should add 16. So, if your volume is exactly 5 G, then your new SG will be 1.061. Considering your volume maybe be a bit more than 5, then your 1.054 reading is reasonable.
....and I now see that your post was 12 days ago, so your fermentation is probably finished. Never mind ;) :mug:
 
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