1st recipe OG 1.66 (target 1.071). I brewed the same recipe today, but left out the specialty grain (1.25lbs Carapils (Dextrine Malt) (US) and 1.25lbs Carastan 30L.) The target OG was still 1.071 per brewtoad. I pitched today's batch on top of the 1st recipe's yeast cake (I am no interested in people's views about this process except as it pertains to my question). Question: Would sediment from the yeast cake, when thoroughly mixed, change the gravity reading? Should I wait till it's settled a bit (I shook it vigorously)? OG was 1.079. Thanks!
It's making the wort denser so it will impact OG, though I imagine minutely. I always check my OG directly from the kettle so I don't have to worry about such things
That makes sense, I can't tell how much I need to top-off till I put it in my ferment bucket though. I guess I should mark the inside of my brew-kettle?
The issue with measuring your OG outside of the kettle is primarily foam. As you mentioned, a kettle measurement would only work with a full volume boil (unless you are willing to calculate the dilution) I think you could go two ways besides calculating, either gently pour the wort and top off water into primary and measure after the foam subsides, or invest in a wine thief to take a gravity sample after dilution
You are exactly right. The foam is a huge pain, even the wine thief ends up foamy. I used a refractometer for the first time today. Picked it up at a yard sale. It seems like it's going to make things much easier but I used a hydrometer today too as a double check.
Particulates in solution will influence hydrometer readings. This statement reflects my experience with soil particle size analyses. While I am sure that the premise extends to yeast cells and hulls in solutions, I'd need to think more to evaluate if it should have the impact you think you are seeing. I suspect it should, but it would depend on the mass of the yeast cake. A 10% beer and limited lighting impair my ability to do calculations on a cocktail napkin, at the moment. That, and I don't actually have a cocktail napkin. Or a pen.
Just let the sample in the flask/hydrometer sit for about 15-20 minutes to drop sediment, decant off into new hydrometer, and take reading.
I have just made notches in the back of my brew spoon for every gallon of volume in my kettle. You can use a piece of CPVC, or whatever you like. You can also do an acid engraving on the inside of your kettle. Additional thoughts: If you remove carapils and L30 malt your OG should drop. If you overpitch, as you pitched on a yeast cake, you might see a lower FG as well.
