Lots of assumptions but here goes...

[Joshua Hughes]

I used the search function first and didn’t find a good answer. I’ve started saving my yeast slurries. I do 1 gallon batches. Assuming no issues with sanitation, beer gravities being similar, hops similar etc. how many tablespoons of slurry for a 1 gallon batch? Im not so cheap that over pitching a little is an issue. No starters just pitching and fermenting.

 

[VikeMan]

To estimate this, you need to be thinking about things like...
How dense is the slurry? How pure is it, e.g. did you rinse it? How old is it? What's the gravity of the batch you'll use it in?
...and then put that information into a yeast calculator.

 

[Jtvann]

Toss in a full cup and wish it the best of luck.

 

[Joshua Hughes]

To estimate this, you need to be thinking about things like...
How dense is the slurry? How pure is it, e.g. did you rinse it? How old is it? What's the gravity of the batch you'll use it in?
...and then put that information into a yeast calculator.

Didn’t rinse. A few weeks old. 4-5% Ale. When i tried to use a calculator it had liters...

 

[Jtvann]

It ain't liters for a 1 gallon batch. I was joking when I said a full cup, as that should be an over pitch. Assuming sanitation is good, that should be a good enough amount assuming its actual slurry and not just liquid. Dont worry too much about over pitching, but a full liter, no way.

 

[VikeMan]

Didn’t rinse. A few weeks old. 4-5% Ale. When i tried to use a calculator it had liters...

So, I'll put your numbers in BrewCipher:

1 Gallon Batch, 1.050 OG
Slurry 28 days old ("a few weeks")
Slurry Density "Average" (default slurry density)
30% Non-Yeast Solids (guessing, can't see your slurry, but not rinsed)

Recommended: 25 ml of slurry

If Non-Yeast Solids were 50%, recommendation changes to 36 ml of slurry

ETA: This is all assuming a standard ale pitch rate of 750K cells / ml / degree plato.

 

[Joshua Hughes]

Lol I know I was just saying that was the default. should be about 4 Oz here

 

[Joshua Hughes]

So, I'll put your numbers in BrewCipher:

1 Gallon Batch, 1.050 OG
Slurry 28 days old ("a few weeks")
Slurry Density "Average" (default slurry density)
30% Non-Yeast Solids (guessing, can't see your slurry, but not rinsed)

Recommended: 25 ml of slurry

If Non-Yeast Solids were 50%, recommendation changes to 36 ml of slurry

ETA: This is all assuming a standard ale pitch rate of 750K cells / ml / degree plato.

Cool thanks.

 

[brew703]

There is other material in the photo besides yeast.
I used to harvest from a brew like you do but quit because of the space it took in my fridge. I had half a shelf of pint size jars. Got tired of my wife complaining.
I now make starters, which you can do. I brew 5.5 gal batches and I harvest two 50 ml vials off of each 2 L starter.
You could probably use one vial for a 1 gal batch but that would probably be an over pitch.
But to your question you could probably start with a T or two of slurry and see how that works. You will never know how much yeast is in a T unless you use a microscope and count.