Consecutive low OG readings

[ChickenSoop]

My first batch was a kit, and my OG ws dead on. so my hydrometer appears to be tuned in.

However my next two - real reciepes - the LME was supplied locally, and my OG was about 8% low both times. I followed the reciepe exactly and final volume was 5 gallons.

Can LME concentration vary between suppliers, or is there a standard quality control rule they have to follow?

 

[hopsalot]

what temperature are you reading your gravity at? What are the gravities? Dont rely on volume to tell you when you are finished until you completely figure out your system.

 

[ChickenSoop]

I have it figured out. BeerSmith shows Pale Liquid Extract potential SG as 1.036. I calculate my local supplied extract is really 1.030. I believe my extract is watered down a bit.

I will change this SG extract value in BeerSmith and up the extract quantity to keep the OG equal.