Originally Posted by RM-MN
Let me see if I can clear up a few things. Suspended solids have nothing to do with the hydrometer reading because if they are solid and suspended they must be the same density as the liquid. It's the dissolved solids that make a difference in the density and in beer those should be sugars. You hydrometer is indirectly measuring the amount of dissolved sugars in your wort.
Ok, let me clear one more thing up. A hydrometer does in fact measure suspended solids (TSS) as well as dissolved solids (TDS), but what it is truly measuring is density of the liquid in comparison to DiHy H20 when calibrated properly (for dairy, sugars, soils or alcohol) and then compensated for the temperature of the liquid. This is why a person may get significantly different readings if you have not waited at least 24 hours after the liquid (wort or otherwise) has been placed in the container. A laboratory grade hydrometer costs at least $200 while your local HBS will sell one to you for only $10-$12. I have used a hydrometer many times in a soil sampling laboratory at the phD level. Sorry to burst your bubble.