How to do gravity on Mead.

[Psywar]

Good afternoon everyone!

I am going to be putting my Cyser into secondary later tonight, but I have a question about getting the gravity readings.

I got the starting gravity at 1.100 and when I re-rack I will grab the ending gravity, but when I re-rack I will be re-racking it onto more juice and honey.

The yeast I used has a tolerance of around 14% so I assume the yeast will reactivate during secondary.

What do I do to continue to calculate the ABV?

Thank you!

 

[JayEff]

Do a weighted average:
1) Take a gravity reading of your second juice and honey addition.
2) Multiply the points of gravity with its volume (say, in gallons - all that matters is you use the same unit throughout the calculation)
3) multiply the 1.100 points of starting gravity with its volume.
4) add those numbers, then divide by the total volume.
This should give you an adjusted gravity reading which takes the total amount of sugar you've added into account, and you can use this to calculate your final ABV.
Example calculation, say you have 5 gallons of 1.100 you start with. Later, you add 1 gallon of 1.200 juice + honey mixture. That makes for:
5 * 1.1 + 1 * 1.2 = 5.5 + 1.2 = 6.7 - divide this by the 6 gallons you have in the end and you get 1.116 as your number to calculate your ABVs with.
If you instead add some volume of the same starting gravity to your fermented mead, your ABV doesn't change.

 

[Psywar]

Thank you very much for that information!

 

[Wovensummers]

Do a weighted average:
1) Take a gravity reading of your second juice and honey addition.
2) Multiply the points of gravity with its volume (say, in gallons - all that matters is you use the same unit throughout the calculation)
3) multiply the 1.100 points of starting gravity with its volume.
4) add those numbers, then divide by the total volume.
This should give you an adjusted gravity reading which takes the total amount of sugar you've added into account, and you can use this to calculate your final ABV.
Example calculation, say you have 5 gallons of 1.100 you start with. Later, you add 1 gallon of 1.200 juice + honey mixture. That makes for:
5 * 1.1 + 1 * 1.2 = 5.5 + 1.2 = 6.7 - divide this by the 6 gallons you have in the end and you get 1.116 as your number to calculate your ABVs with.
If you instead add some volume of the same starting gravity to your fermented mead, your ABV doesn't change.

I realize this thread is several months old, but it comes the closest to my question. I didn't measure the SG of the added materials. I started with 1 gallon of mead, OG was 1.092. It was in primary for 3 weeks and bubbling had slowed to one bubble every 8-10 seconds. SG was 1.020. I racked off the 1/2" of lees and added 12 oz of frozen (thawed) juice concentrate and 16oz to water to top off. SG is now 1.030. Is there a way to calculate final ABV at this point? Is it as simple as pretending the OG was 1.102?

 

[myndflyte]

From what I understand about it, yeah it's as simple as that.

 

[biochemedic]

...Is it as simple as pretending the OG was 1.102?

Yes. It doesn't matter when the fermentables were added...
Just add the measured 10 points to your initial OG.