Fermentation different in two carboys

[turbo 6]

I have a question, not too much of a concern, but I made a starter for a 10 gallon batch I brewed yesterday. The starter was 1000 ml and was pitched into two separate carboys. Both are in the chamber @67-68*. One is chugging like no tomorrow and one isn't. Both have tilt hydrometers in them and the chugging one is consistently reading lower gravity than the other one. I've noticed this on all 10 gallon batches I've brewed. One chugging and one lagging, but both beers end up tasting the same. What causes this?

 

[day_trippr]

I brew 10 gallon batches and use glass carboys and when I use the same yeast strain both fermentations will be apparently identical. For that matter I've been using similar but different strains (eg: 1318 and a38) between the two carboys on a lot of brews of late and even those from all appearances progress the same.

Assuming both carboys "see" the same environment there's not much left: if you're pouring out "half" from a single flask, I expect that's where the mystery would resolve...

Cheers!

 

[turbo 6]

Poured 500 ml from the flask into both. So yeah half but not a visual half. I've noticed the same thing with two different packs of US 05 and 1318.

My gravity is dropping in the lagging one but not like the chugger.

 

[flars]

Seems like one fermentor was pitched with more yeast cells than the other. How many cells do you estimate the one liter starter propagated accounting for the age of the yeast? What was the OG of the beer?

 

[turbo 6]

Well after further investigation I found my airlock leaking. It has a ton of activity once I seal it off.