Not sure if this is wise but I occasionally use a sanitized stainless steel baster to draw out a scant couple few inches of wine and drop the hydrometer into the carboy (3, 5 or 6 gallon sizes) even if the SG is at 995 there is still enough hydrometer above the surface of the wine for me to pull it up and return the wine I withdrew with the baster. My hydrometer is too long to effectively measure the gravity of wine in one-gallon carboys.