OG and large starter

[ampsman]

I made an imperial stout a couple of days ago and ended up with an OG of 1.09 before I added my starter. After adding the 2l starter I took another gravity reading since I knew it would be diluted and had 1.086. I usually crash and decant large starters but unfortunately didnt have time.
So my question, is 1.086 my true OG?

 

[kh54s10]

I would say yes. But then I would ask, does .004 really matter to you? Why?

 

[jjw5015]

If that's what the hydrometer said...

 

[woo_pig]

Well technically no. Because you did add some alcohol in. But like he said not to much to worry about .

 

[kh54s10]

Well technically no. Because you did add some alcohol in. But like he said not to much to worry about .

The OG is what the hydrometer read. As is the FG reading. The alcohol content is another story.

If using the OG to calculate the ABV, it will be off very slightly due to the alcohol added with the starter.

 

[woo_pig]

The OG is what the hydrometer read. As is the FG reading. The alcohol content is another story.

Yes it's kinda a measurement from point a to point b.

 

[ampsman]

I would say yes. But then I would ask, does .004 really matter to you? Why?

haha, no doesnt really matter. It just got me thinking.
I guess I was more curious about how accurate the final ABV calculation would be going strictly off the hydrometer.

 

[kh54s10]

1.054 OG to 1.010 = 5.78% alcohol by volume.
1.050 OG to 1.010 = 5.25% alcohol by volume. Skewed a tiny bit by the alcohol in the starter "beer"

So there is a bit of difference, more than I expected. But I don't think I would notice the .53%

 

[jjw5015]

1.054 OG to 1.010 = 5.78% alcohol by volume.
1.050 OG to 1.010 = 5.25% alcohol by volume. Skewed a tiny bit by the alcohol in the starter "beer"

So there is a bit of difference, more than I expected. But I don't think I would notice the .53%

But the OP beer was 1.09 so it will be significantly smaller difference.

 

[kh54s10]

1.054 OG to 1.010 = 5.78% alcohol by volume.
1.050 OG to 1.010 = 5.25% alcohol by volume. Skewed a tiny bit by the alcohol in the starter "beer"

So there is a bit of difference, more than I expected. But I don't think I would notice the .53%

But the OP beer was 1.09 so it will be significantly smaller difference.

I just ran that as an example.

 

[DaWhip]

Assuming the starter was approximately the same OG/FG as the wort, final ABV would be the same. The initial addition of the starter dilutes the sugars as seen on the hydrometer, but final ABV should not be adjusted.