Hydrometer Reading Questions

[wetneck]

Ok, im confused about reading a hydrometer when you have solid fruit when making the must.

Im doing strawberry wine attempting a 4 gallon batch in a 5 gallon bucket. I probably should have looked around for a 6 gallon food grade bucket instead but here i am.

This is my first attempt at making a fruit wine like this and also starting a blackraspberry must.

The most confusing thing to me is how is the hydrometer going to read the sugars inside the fruit?

Is there a way to estimate that?

 

[FlamingoEmporium]

Your initial reading is taken when your fruit and water and enzymes have been sitting in your primary bucket before pitching the yeast. Fruit is usually crushed or thawed from frozen and that releases the juice and sugar.
then you add sugar to get your desired starting SG

 

[BarrelMonkey]

In a professional wine chemistry lab they typically crush the fruit in a blender and centrifuge it to remove the solids before measurement. Since we don't usually have a centrifuge lying around the house, an alternative is to strain and filter the solids after blending and before measurement. You can use a fine kitchen strainer as a first pass and then optionally a coffee filter paper to get it nice and clean. (Just the fine strainer should be OK for a hydrometer reading; I'd be inclined to do the filter paper step if you're going to measure pH and/or TA with a pH meter/probe.) As long as your equipment is sanitized it's OK to add back the juice sample to your primary fermenter so that you don't lose it.

 

[barryjo]

My theory is that if something (solids) are not dissolved in the liquid, they will not affect SG. You may have to spin the hydrometer to get an accurate reading but the final will be accurate. For example, if you add marbles to a liquid, they will not increase SG. It may be that very fine
Particulate matter will have some effect but Not enough to alter the readings.

 

[winemaker81]

The most confusing thing to me is how is the hydrometer going to read the sugars inside the fruit?

I use a FermTech wine thief, which is large enough to hold a hydrometer. I wrap it in a fine nylon straining bag and pull enough liquid to read the hydrometer, then release the liquid back into the fermenter.

Note -- keep the thief and hydrometer clean, and sanitize before use.

 

[sour_grapes]

My theory is that if something (solids) are not dissolved in the liquid, they will not affect SG. You may have to spin the hydrometer to get an accurate reading but the final will be accurate. For example, if you add marbles to a liquid, they will not increase SG. It may be that very fine
Particulate matter will have some effect but Not enough to alter the readings.

This theory is not correct. The solids do not have to be dissolved, just suspended, to affect the SG reading. Anything that is suspended contributes.

The marble counterexample is not germane: In that case, those solids are NOT suspended.

Think of it this way: Anything that has to move up in the column of liquid when the hydrometer is inserted affects the reading.

 

[wetneck]

This theory is not correct. The solids do not have to be dissolved, just suspended, to affect the SG reading. Anything that is suspended contributes.

The marble counterexample is not germane: In that case, those solids are NOT suspended.

Think of it this way: Anything that has to move up in the column of liquid when the hydrometer is inserted affects the reading.

Thank you