The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Yeast Question

SoulPainter's picture
SoulPainter

Yeast Question

Hi Bakers, How long will a cake of fresh yeast keep in my fridge? Thank you.

Mini Oven's picture
Mini Oven

between the store and your fridge.  You might want to freeze it if keeping it longer.  It may keep even longer if resting on a bed of baking soda.  (Mine once fell into my soda dish and I discovered it still good a month later.   ... it can't hurt.)

SoulPainter's picture
SoulPainter

I stuff I buy has no date. It comes bulk

Syd's picture
Syd

I usually buy fresh yeast in 500g bricks (looks like a brick of butter) and then I cut it up with a sharp knife into 15g pieces.  I wrap each piece individually in cling film and then place all of them into a seal-able plastic container and put it in the freezer.  It lasts for ages this way.  How long exactly?  I can't be sure, but I have used it up to six months later with great success.  It is important to cut it up into manageable pieces because, once frozen, it will take a hammer and chisel to break apart.  15g is a convenient weight for me as it is the amount I will most often use.  Just cut it up into whatever size blocks are convenient for you. Admittedly, though, I have been using less and less fresh yeast recently and more often than not opt for instant yeast.  Your question has piqued my interest, though, and I have some fresh yeast in the freezer which is more than a year old and I think I might just see how it works this weekend. 


Fresh yeast doesn't keep for very long in the fridge.  I had some go all soft and mouldy on me in the fridge.  Like a soft Camembert or a Brie.  I can't remember exactly how long it took to go like that but it might only have been a few weeks.


Syd

mrfrost's picture
mrfrost

The only time I used fresh yeast, I stored it in my basement refrigerator, which is very cold. Probably just a couple degrees above freezing. Guessing 35 degF.


Kept the yeast in a plastic zip loc bag, and removed as much air as possible each time I used it. Right at about 60 days, just as I was using the last of it, I noticed a greenish mold beginning to grow on it. On the last piece, I chipped off all the mold and used it. Still worked fine.


I think it's normally recomended to use within 30 days(if refrigerated).


ps: Red Star recommend usage within 10 days for their retail, fresh, cake yeast.

Elagins's picture
Elagins

the key thing to remember about fresh yeast is that it's a colony of living organisms (fungi) that digest sugar, respire and excrete CO2. Freezing kills them by turning the internal moisture into ice crystals that destroy genetic material and cell walls. Freeze-dried yeast and previously frozen yeast works because the spores survive, but not the fungi themselves. If you want to know what happens when you freeze fresh yeast, stick a mushroom in the freezer overnight, then thaw it out.


keep your fresh yeast in a loosely covered container -- either a plastic bag that's left slightly open or a food storage container that's open enough to let the CO2 escape, and keep it cold -- that 35 degree number is a good one. Under those conditions, the yeast should keep for 2-3 months.


Best way to tell if fresh yeast is still viable is to break a piece off: if it crumbles, it's good; if it's gooey, like butter, it's DOA.


Hope this helps


Stan Ginsberg
www.nybakers.com

SoulPainter's picture
SoulPainter

Thanks for that.

Syd's picture
Syd

So would that explain while it would still work but, perhaps, not as effectively?  Thanks for that information.  My problem is that I can only buy it in 500g bricks and I can't use it up that quickly so I have to do something with the excess. Mind you it is really cheap, but I still hate to waste any.


Syd

Elagins's picture
Elagins

if you want/need to use up as much of the yeast as possible, i suggest baking sweet yeast pastries, which typically contain in excess of 10% each of sugar and fat -- yeast-raised doughnuts, coffee cakes, danish pastries, etc. highly enriched doughs actually inhibit yeast, so sweet yeast formulas typically call for 5% to 10% (sometimes more) fresh yeast to flour.


re: your first point, not all the yeast cells die -- just as not everyone exposed to sub-freezing temperatures dies, but if you're exposed long enough, metabolism slows and stops and all kinds of other nasty things happen, so between the barely live cells and the spores, yes, the yeast will remain active, but not nearly at the level it would if the colony is kept under ideal conditions -- slowed metabolism, but not completely stopped.

kaaskop123's picture
kaaskop123

why not using instant yeast?  it is so much easier so much more convenient to use instant yeast. I challenge anyone to prove me different.


kees

Mini Oven's picture
Mini Oven

I did it all the time when living in Indonesia.  I had more problems with the instant being exposed to heat before I got it (very dead) than a frozen cube of fresh yeast.  The frozen fresh yeast worked.  Can't remember a problem using it.  I used instant as I didn't have a refrigerator, but kept fresh frozen in the office freezer as back up when the instant failed.  I had to go 33km to the nearest town big enough to buy instant.  I could bike to the end of the village and get to the freezer and return inside 1km.  


If I knew what I do now about sourdoughs, I would have kept a starter in my cooler next to the ice block, the cold bottle of beer and the rehydrated instant milk.  Gosh that was 20 years ago!  My how things change!  


 


 

Syd's picture
Syd

Mini, I can't remember having a problem with it, either.  If I read Stan correctly, though, he is saying that it isn't going to kill it entirely, but it is going to reduce its efficacy.  However, in this tropical climate, freezing is definitley the lesser of two evils.  It would spoil long before I could use it up unless I froze it.


Having said that, it has been a while since I used fresh yeast.  I used to believe it gave the bread a better flavour, but now I think I was perhaps just fondly imagining that! I don't know.  Will have to do some experiments again.  I have some pretty old frozen yeast in the freezer.  Will be interesting to see if it still works.  For the moment, if I am not using sourdough, I use instant yeast.  But as you say, instant yeast is not infallible, either.  A while back, on my way home from the baking store, I bought some noodles (with very hot soup) tied up in a bag, as is the custom here in Asia, and absent mindedly put it right next to my newly bought instant yeast.  Well, that was the end of the yeast.  Fortunately, it was only a small amount, but I learned my lesson. 


Syd