How long can fresh yeast be frozen?
I've heard that I can actually buy a large box of fresh yeast cubes, freeze it, and take one out of the freezer twelve hours before using it, to let it slowly get to room temperature again.
How long can I freeze the yeast for? Will it slowly degrade, or will it just be suddenly unusable after a certain length of time?
A lot of people seem to be sharing the opinion that fresh yeast doesn't last long/is 'highly perishable'. However, I have made quite the opposite observation... I've bought fresh yeast from the supermarket, carried it around for about 16-20 hours with about 20 degrees Celsius or more outside two times; both times, I put the stuff back in the fridge to see if it still worked. And yeah, it did (I always first put it into a bowl with a little sugar and luke warm water). I also once kept my yeast weeks longer than the best-by date would have suggested. No problem.
I'm not a biologist, but I reckon biology says yeast (yeah I know, not exactly your supermarket kind, but still...) has been around for ages, and also been used long before everybody had fridges in their homes... so.. maybe it's not as perishable as most people are led to believe (it isn't, as I have discovered).
The reason dry yeast is so popular is that it is easier to store, and is less persnickety about it than fresh yeast. Treat dry yeast right and it can last for a couple of years or more. Fresh yeast is highly perishable, and it should be frozen if you're not going to use it within a couple of days. If you're lucky, you can get significantly more time from fresh yeast by freezing it within just a day or two of getting it home.
The thing is, yeast is a living thing and you just can't know what experiences it has had before arriving in your kitchen. As such, it's impossible to predict just how much extra (past the expiration date) time you are going to get from freezing it. A month? Probably. Two months? I wouldn't count on it, but maybe. 6 months? Highly unlikely, but stranger things have happened.
If you do freeze fresh yeast, wrap it very well. Moisture and air are your enemies. Do put it in the refrigerator at least 12 hours prior to use, then let it spend the last hour on the counter. As a last step before putting together your dough, proof it. Proof the yeast by mixing it with the warm (100Fish) water called for in the recipe and, if applicable, the sugar. If there is no sugar in the recipe, give it a 1/2 tsp of flour (per loaf). Within 5-10 minutes it should be quite bubbly and growing. If it doesn't look like it's doing much, throw it away. You might as well throw away all of the yeast you have from that batch. Go to the store and get more yeast before proceeding with the recipe.
Properly stored, yeast usually dies at least somewhat gradually. You may see a slight progressive decrease in the vigor of your yeast as it gets older. Personally, once I see that I'll use it that time, but I'll get more for next time.
Anymore, fresh yeast is hardly seen except in professional bakeries. It's easy to see why. If you're going to make multiple loaves in a week, then maybe fresh yeast is worth it. Now that I have found 2 pound packages of Fleischmann's instant dry yeast (expiration almost 2 years out) at Sam's Club for $6, I think my days of messing with fresh yeast are over. (BTW 2lbs of dry yeast = about 130 loaves)
EDIT: Interestingly, Red Star disagrees and doesn't recommend freezing fresh yeast. This goes against my experience and the cynic in me wonders of their recommendation has more to do with selling yeast than anything else.
Their recommendation almost certainly has to do with quality outcomes. Freezing is not good for yeast. A significant portion of the culture in the fresh yeast will die, degrading its potency and furthering the fairly unpredictable nature of how fast it will proof.
Well I wouldn't recommend buying fresh yeast today, freezing overnight to bake tomorrow, but I have successfully baked with 4 month old fresh (frozen) yeast. How *fast* it proofs is less of an issue if you do, in fact, proof. I'd rather have "maybe" in my freezer than *dead* in my fridge.
If it were not directly non-responsive to the question, I would recommend eschewing fresh yeast all together. There is absolutely no benefit today.
Thanks for this ... I disagree with the "fresh yeast is hardly seen" bit though - probably for the same reason that the brand names you and @SAJ14SAJ mentioned don't ring any bell with me - I'm in germany and not in the US. I've hardly ever used dried yeast, which is why I've asked this question in the first place.
Really? I was born in Germany [that is just an aside, it means less than nothing] I find it amazing that you find it difficult to get 'active dry yeast'.
No, that's not the case, it's as easy to get as fresh yeast, just that no supermarket seems to have anything else than 3*7g sachets, and I simply didn't fancy buying 50 of those to store them somewhere - those seem to distribute themselves within the kitchen cupboards a lot more than a few cubes of fresh yeast within the fridge. Also, most of the recipes I use call for fresh yeast, and so far I haven't been tempted to convert them.
@takrl Buy a tupperware box which can hold 50 of them and store the box in a cupboard, problem solved. The reason why they sell it this way is that this is indeed the option most easy to store. A large package of dry yeast starts ageing once you open it, so people store it in the fridge or freezer once opened, which is less convenient seeing that cupboard space is usually less constrained than freezer space. And live yeast not only eats fridge space, it dies easily. "Converting" a recipe to dry just means to take exactly 1/3 of the given amount in weight and follow the steps as with fresh.
@rumtscho I'd agree with the storage option if I was the only person using that kitchen. I'm not, and frequently I have to search for items that were put 'somewhere' instead where they belong. Same goes for loose sachets of [put ingredient here] - I've simply given up on that.
Plain and simply, no. In my life as it currently is, there simply is no solution to that problem. But we're digressing ... fresh yeast is what most of my recipes call for, as I already mentioned. I really just wanted to find out if freezing yeast is a viable thing for me to do, since I'm using two to four cubes a week.
Freezing yeast is certainly viable (brewers do it all the time). You just need to use a 25% glycerin solution to keep the cell walls from being damaged by ice crystals.
Hmm, all my dry yeast packets are in the fridge (as is my dry yeast from a large package, transferred to a jar - as is my dry brewing yeast.) In a possibly related anecdote, I've never had dead yeast (even long after expiration dates.) When storing/culturing brewing yeast for re-use, I use the simple in water, in the fridge method, and many years later it is generally fine. http://www.brewery.org/brewery/library/SterileDW1096.html I don't bother with that for baking yeast, but see no reason it would not work as well.