Not understanding the maths here

[makaholic]

Just making some red from blackcurrant cordial which of course has a lot of added sugar, I did my maths & recipe like this for a 5 litre / gallon DJ although its ended up as 2 Gals because I had to add extra water to get the SG to1.080 ish
3 litres Waitrose blackcurrant cordial boiled to rid preservative sugar content 630g per litre
2 Litres Waitrose red grape juice no preservative 160g sugar per litre
1 can winemaking red grape concentrate unknown sugar content
2 tsp Nutrient
2 tsp Tannin
1 sachet of K1-v1116 yeast
Water to make 10 ltrs 400 mls
Sugar worked out as
18g sugar to make 1% alcohol I wanted about 12% so needed 1,080 g sugar
( 12%x5x18g sugar = 1.080)
cordial sugar 630g x 3 bottles = 990
Red grape juice 160g sugar x 2 cartons = 480
990+480=1,470. But now have 10 litres and this should not be enough although SG is fine.
First I had added 2 ½ ltrs water but SG was 1,120 far too high so added water until SG 1,083 which is how I ended up with 10 ltrs 400 mls.

Now am I on the right track here or gone right off!!!???

[NorthernWiner]

I'm not certain because, first, I don't know the sugar level of all your ingredients and, second, I don't measure SG.

But one thing I would suggest for the future is to first add everything except the sugar. THEN take a SG reading. Once you have that, then it's easy to calculate how much additional sugar is required to bring it up to the desired level.

Maybe that's how you did it, but I was a little confused by your post.

Also, I notice you said "unknown sugar content" when referring to grape concentrate. I believe canned grape concentrate (for winemaking, not the breakfast juice product) is almost universally 68 Brix, or 68% sugar by weight. If that helps at all.

[Cellar_Rat]

Waitrose red grape juice, I think is drinking juice.

Like steve says: You are better off, reading the SG first and then adding the sugar.

Better still. Spend £10 on ebay and get a refractometer with a the brix/%alc scale. Job done ... and the maths is easier ... and they don't roll off the bench and break into a millions pieces.

The problem with diluting it down is that everything get diluted not just the sugar.

This hobby is all about learning. It will ferment - it will be drinkable. Don't panic - it will be different next time.

[makaholic]

Thanks guys, I was confused by my own mail too!!!!!! I actually didn't add any sugar at all as it was so high in content naturally which is a bit of a problem when using cordial type drinks me thinks, interesting about the sugar content of the RGC will rember that for future calculations, would have been a help if it were disclosed on the can!!!!!!!!!!!!

Definitely feel a refractometer coming on, have had my eye on one for a bit!

And yep I realised that everything would get diluted sadly but didn't have any other answers if I didn't want a very high alcohol content how to get the sugar level down all a good learning curve.

[Cellar_Rat]

If you do get a refracto - double check the scale is the one you want - they come in a miriad a ranges AND scales. So even if the range is >25% make sure the scale is wnat you want.

[makaholic]

If you do get a refracto - double check the scale is the one you want - they come in a miriad a ranges AND scales. So even if the range is >25% make sure the scale is wnat you want.

Ah now that is interesting I didn't realise that, can you point in a direction of what I should be looking for regarding wine making purposes cos I don't know what scale I do want or should have Also amazed they can be found for as little as a tenna on e bay, they are around 70- 80 quid...ish I think from the wine suppliers.

[goldseal]

Neither a hydrometer nor a refractometer will enable you to calculate how much sugar you need to add to get to a certain starting SG.

My advice would be:

a) calculate how many grammes of sugar you have in your base ingredients
b) you know the volume of your must, so convert to grammes per litre.
c) use this chart:

http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm

- use the first 'sugar' column to find your grammes per litre, and read off your SG.

If you want 1.080 as your starting SG, you need 215 grammes per litre. If you have less, simply calculate how many extra grammes per litre you need, then multiply it by the number of litres you have.

NOW DO AS STEVE SUGGESTS - make up your must minus the additional sugar, and check the SG with your hydrometer. If the actual reading varies from your expected reading by much, you can now recalculate the sugar addition.

Now add the sugar a bit at a time, and keep checking the hydrometer reading.


What starting SG do you need? It depends on the style of wine you are making. Assume you start at 1.080 and the fermentation is expected to stop at, say, 0.992, you can do this calculation:

(1080 - 992) / 7.36 = alcohol content.

In this case, you'll get more or less 12% alcohol. This is APPROXIMATE, but good enough for our purposes. If you want more or less alcohol in your wine, just raise or lower the starting SG figure as appropriate.

Doing everything in grammes per litre, then converting back to SG, works well. You could convert to Brix instead of SG on the same chart, should you choose to use a refractometer instead of a hydrometer.

[makaholic]

Thank you that is really helpful and will keep the info to hand. I did try to work out my sugar content as mentioned in my original mail and for one gallon of wine ( which I had started out to make) it was sugar heavy so didn't add any sugar at all just water to get the content down which took pretty much another gallon of water, but the maths now do not add up for a 2 gallon/ 10 liters of juice batch considering I now have an SG1.083?? but I have gone by the SG reading rather than the maths which tell me for 2 gallons I should need to add sugar cos for 2 gallons I really need 2k.160g sugar but the content of my juice which already had a sugar level of 1K.470g sugar too much for 1 gallon but not enough for 2 gallons, and it is this I cannot understand where it all went wrong, but it seems to be fermenting well at the moment and will do the maths from my SG reading and leave it at that until next time then follow your instructions