Effect Of Suspended Yeast On Gravity Reading?

[Nick JD]

Yeast isnt soluble in water, it doesn't disolve. It is suspended in the water and since heavier will increase the density of the solution.

Cheers
Jason

Of course yeast doesn't dissolve. Where did I say that?

Oh and please prove to me that yeast is denser than wort. The trick here might involve your use of the word, "suspended". Had you have used the word, "sunk" or "float" I might not ask this. At most I would guess yeast has roughly the same density of a fresh wort and is probably why it settles out during the end of fermentation.

Which begs another question: what is the biomass of yeast during fermentation? What is the ratio of wort to yeast?

What is a human's specific gravity (I'm not talking about fat people - we all know they float!) who has just drank five liters of beer?

 

[OzMick]

Oh and please prove to me that yeast is denser than wort.

Centrifuged beer will have the yeast pulled to the bottom.

Edit: Ok, so that is still using beer as an example. From http://www.wyeastlab.com/com-yeast-harvest.cfm

1L (1 quart) of yeast slurry (40% yeast solids) weighs approximately 1.1 Kg (2.4 lbs.).

So, 1L of pure yeast solids by that would weigh 1.25kg. So is denser than wort.

 

[Nick JD]

So, 1L of pure yeast solids by that would weigh 1.25kg. So is denser than wort.

Are you assuming the other 60% in a yeast slurry is water?

I've read yeast is around 1.075-1.080 SG. That a bit different than 1.250. These yeast cells are denser than me?! I've got bones!

 

[drtomc]

The SG of aluminium is 2.7; lead is 11.3. See, it even works for solids - although how you get your hydrometer into a block of lead beats the hell out of me. :lol:

I've attempted to get several into the floor tiles over the years, and have not succeeded yet, so I cannot report their SG. :lol:

T.

 

[bum]

These yeast cells are denser than me?!

h34r:

 

[Jazzafish]

To be simple, yeast/break/anything in the solution being measured will influence your reading.

To be as close as possible to a correct reading, pour samples through a paper filter. Or you could have a bit of fun with a home made centrefuge... jar on an end of some rope, swung around for a while! :lol: Pour the liquid off the compacted cake in the jar and your all set for a precise reading!!!