Yeast: Types, Use, Storage, Conversions (instant<>active, US<>UK, etc.)

[dougal]

... I use instant yeast, bought at BJs so in 3 large vacuum sealed packages. I have one in the freezer, one in the pantry (sealed) and one opened in the pantry that I've been using. Expiration date is Sept. 2009. ...

If I keep the packages freezed, how long past expiration date will they last? Months or more like a year or more?

Dunno about your yeast, sorry.

I think that at cool temperatures, Instant lasts for years if its left sealed in its original package.

The open package I've been using seems to not be "working" as well as it has been. The last 2 batches didn't rise nearly as much in the same amount of time. The first lower rise batch was still ok but noticable less risen... but baked and tasted fine. Only I noticed any difference from previous loaves. The most recent low rise bread (significantly less rise in same timeframe) was quite dense/heavy and while it tasted fine, it was well, dense and heavy. Great toasted though!

So... is my yeast dying?

Yes, I'd say there's a lower proportion of viable yeast than there used to be.

Can I simply use more in the recipe to compensate? Should I use the same amount of yeast but plan for a much longer rise time? Do I chuck the unused yeast (well, at least it'll help my septic tank so not a complete loss!), open a fresh package but keep the unused part in the freezer instead of the pantry? If so, do I need to brng the yeast back to room temp before using it in a recipe? ...

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You could use more (to generate more gas in the same time), but you'll get a stronger taste of yeast. Some people like that. And the dead yeast will give you glutathione. So your dough will stretch more without tearing, but it won't be as "strong". So your bread won't hold as much rise. Hence IMHO it'd be better for pizza than well risen bread!

Giving it more time will likely emphasise this weakening effect.

Personally, I'd bin it. No idea what it might do to your tank, but it couldn't harm on the compost heap...

I buy Instant in packs of about 100g (costing about £1 IIRC.) Once opened, I decant the whole pack into a jamjar, which then lives, tightly closed, on a fridge door shelf. It lasts pretty damn well. And is used direct from there.

I wouldn't leave a large open pack "in the pantry" where it is exposed to warmth, and more importantly the humidity that the original pack was sealing out.

As long as its dry, I doubt freezing would do much harm to Instant Mix yeast. Don't know how much good it'd do.

[Starkman]

As noted in my (March 26th) post above, my understanding is that

10g fresh/compressed = 4g actively dried = 3g instant mixing yeast

which implies that 1 oz actively dried would equate to about 2.5 oz of fresh/compressed.

Thanks, but I'm still not sure, then, how to deal with chiantiglace's posted formula (100%, 50%, 33%).

Your formula hits on with the chart, but chiantiglace's doesn't (at least not as I'm understanding the formula); yet it seems to be acceptable. How is that?

Thanks,

Starkman

Edited October 7, 2008 by Starkman (log)

[tino27]

As noted in my (March 26th) post above, my understanding is that

10g fresh/compressed = 4g actively dried = 3g instant mixing yeast

which implies that 1 oz actively dried would equate to about 2.5 oz of fresh/compressed.

Thanks, but I'm still not sure, then, how to deal with chiantiglace's posted formula (100%, 50%, 33%).

Your formula hits on with the chart, but chiantiglace's doesn't (at least not as I'm understanding the formula); yet it seems to be acceptable. How is that?

Thanks,

Starkman

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I assume you are talking about the 40% vs. 50% difference? Every reference I have come across has listed 40% for fresh->active dry conversion. Some people may use 50% because it is easier in their heads to divide an amount in 1/2 (50%) than to try and multiply it by 2/5 (40%). Honestly I think it may just be more convenience than anything else. That's one of the nice things about fresh->instant conversion: simply divide by 3.

[jlwquilter]

Thank you all for the information! My "open package in the pantry" is in a former plastic frosting container but I am going to move it to the fridge and store my "current usage yeast" inthe fridge from now on. I live in southeast FL so hot and humid BUT have the AC cranking most days so it can get cool in the house. Maybe the AC was cranking more than usual that one/two days.

My third batch with the questionable yeast came out just fine, although I did add a teensy bit more yeast than normal, did let it rise longer (but not crazy longer) and at one point I did put the loaf pans into a pan of warm water.... so in may ways incorporated the suggestions made! And if that is what I need to do until I use that batch of yeast up, I can live with it

FYI: my young daughter had to come up with a science project for class. We decided to do comparisons of yeast... instant, active dried, and rapid-rise (bread machine) yeasts... which would rise fastest given same time, water, flour, sugar, temperature, etc. The instant yeast rose quite a bit faster than the other 2. However, given a longer time frame for rising, the rapid-rise yeast caught up to the instant yeast. Active dry was "left in the dust".

But now given what I am reading here, a faster rise isn't necessarily a good thing! I am a home baker and we love the bread I make but I won't say that it's the best ever made certainly. I'd like to improve the bread... should I go for a slower rising yeast after all?? Or when I have time (yeah, right) rise the dough in the fridge?

Hmm... maybe I am getting off topic for this thread. If so, I apologize!

[tino27]

I don't want to hijack the topic either, but I will say that for bread, time = flavor. An overnight rise in the fridge is a very common way of adding flavor to the finished product. Good luck with your baking.

[Sher.eats]

hey all, first post on the baking forums!

I've been given some "fresh yeast" (from France apparently). it's "alive" as I mixed 1 tbsp of the yeast with 4 tbsp of flour and 4 tbsp of water with a sprinkling of sugar (I didn't know what the correct ratio should be), after a few hours the mixture was very alive and nearly filled the bowl (room temp around 20C), so the yeast is "good".

I'm trying to make a no knead bread using this yeast (done it before with baker's yeast), and am using this recipe.

1) It asks for "1 cup fully active sourdough culture" <- how to I make this (yeast:flour:water:sugar ratio, time, temperature)

2) It asks the final dough to be placed in a cool oven for optimum oven spring, I thought that happens when the alcohol evaporates and inflates the tiny air bubbles, wouldn't a hot oven do that faster before a crust develops?

=

non-recipe related fresh yeast questions

3) how long will the butter-like yeast last in the fridge?

4) is there a difference in the bread flavour produced by using (a starter made by this fresh-yeast which I already feed/kept alive for days/months/years) vs (a "fresh" starter made a few hours ago)

5) yeast turns glucose into alcohol, bacteria turns alcohol into acid...in a starter flour is used up but the acid will build up over time (or where does it go) and eventually it'll be too acidic for the yeast and it dies...right? if so how does one keep a starter going....

very very beginnger questions...

thanks!!!!!

[DanM]

Let me preface this by saying that my experience with bread is limited to being a serious home baker and training in culinary school. I do not have any experience working in a bread shop.

Lets break this down for you.

1) It asks for "1 cup fully active sourdough culture" <- how to I make this (yeast:flour:water:sugar ratio, time, temperature)

That depends... does the recipe call for a stiff or liquid culture? I recommend that you get your hands on Peter Reinhart's Bread Bakers Apprentice or Jeffery Hammelman's Bread. Here is Peter Reinhart's instructions for making a starter. http://books.google.com/books?id=yHGBOXSNo...nhart#PPA227,M1

2) It asks the final dough to be placed in a cool oven for optimum oven spring, I thought that happens when the alcohol evaporates and inflates the tiny air bubbles, wouldn't a hot oven do that faster before a crust develops?

Partially correct. Oven spring happens when yeast reproduce wildly just before meet their maker. This creates pockets of CO2 that expand while baking. As the bread bakes, the moisture turns to steam and gives you your oven spring. You can improve the crust by steaming the oven and baking on a stone.

3) how long will the butter-like yeast last in the fridge?

Until the date on the package...

4) is there a difference in the bread flavour produced by using (a starter made by this fresh-yeast which I already feed/kept alive for days/months/years) vs (a "fresh" starter made a few hours ago)

First, you do not make starters with fresh yeast. The beasties you need are actively living in your kitchen, you just don't know it!

The starter is only as good as the beasties that CURRENTLY live in it. You can find people who are willing to sell you starters from San Francisco and many exotic locations. In a very short amount of time, the beasties from those exotic locals will be displaced by local beasties and change its flavor to anything you find locally.

5) yeast turns glucose into alcohol, bacteria turns alcohol into acid...in a starter flour is used up but the acid will build up over time (or where does it go) and eventually it'll be too acidic for the yeast and it dies...right? if so how does one keep a starter going....

Regular culling and feeding. You will occasionally feed the starter by throwing out most of the starter and feeding it with fresh water and flour.

Best of luck

Dan

[Lisa Shock]

If wrapped tightly, and stored in the fridge, your yeast should last 3-4 weeks before losing strength.

[jackal10]

You have fresh yeast cake. It will keep a few weeks in the fridge.

it is NOT sourdough starter/culture - different yeast and no lactobaccillus.

You can make a yeast starter ("poolish") to use in your recipe, but the bread will be ...different. Not better or worse, just your bread.

Fresh bakers yeast will ferement about twice as fast as sourdough, so you will need to adjust the times.

To try and answer your questions

1) It asks for "1 cup fully active sourdough culture" <- how to I make this (yeast:flour:water:sugar ratio, time, temperature)

Make it like you did before: 1 tsp yeast, half a cup water, half a cup flour and leave in a warm place (75F) for a few hours. No point in doing the 12-18 hour fermentation, as this is not sourdough.

2) It asks the final dough to be placed in a cool oven for optimum oven spring, I thought that happens when the alcohol evaporates and inflates the tiny air bubbles, wouldn't a hot oven do that faster before a crust develops?

He uses the bake from cold trick to give a period of proving befoe the oven ges hot enough. ALcohol is not the primary inflation - CO2 and then steam is. However baking in a pre-heated big caserole with the lid on for most of the bake is a very good idea and simulates a professional oven.

non-recipe related fresh yeast questions

3) how long will the butter-like yeast last in the fridge?

3-4 weeks. Keep covered.

4) is there a difference in the bread flavour produced by using (a starter made by this fresh-yeast which I already feed/kept alive for days/months/years) vs (a "fresh" starter made a few hours ago)

Not really. A fresh starter will work better as an old starter will accumulate by products that will slow the yeast down, However using a smaller amount of orignal yeast allows a longer fermenation and slightly different flavoured bread, but get the basic recipe working well for you first.

5) yeast turns glucose into alcohol, bacteria turns alcohol into acid...in a starter flour is used up but the acid will build up over time (or where does it go) and eventually it'll be too acidic for the yeast and it dies...right? if so how does one keep a starter going....

This is yeast, so no bacteria.

Also that is not really what is happening in a sourdough starter. The lactobacillus break the starch down into sugars, that the yeast then ferments.

For a sourdough starter you refresh the starter every once in a while by effectively starting from fresh with flour and water, and a spoonful of the old starter as an innoculum, throwing the rest of the old starter away to get rid of the acids and other by products that have accumulated.

Edited December 28, 2008 by jackal10 (log)

[chef koo]

what's the general consensus (if any) on which is better out of the 2 types of yeast? i'm not sure if it's just hearsay but apparently yeast technology has advanced so far that there's almost no difference. can this rumor be substantiated?

[Tri2Cook]

I don't know what the general consensus would be, but I use dry. Then again, I'm not a bread artist. I just make a lot of burger buns and pizza dough (white and whole wheat).

[ilikefood]

I vote for dry but it must be instant dry yeast NOT active dry yeast (the expensive yeast in small packets usually found at any grocery store). Instant dry yeast does not need to be activated/rehydrated in water like the active dry yeast does. I buy the instant dry yeast at a small bulk foods store under the name SAF. A one pound block usually costs around $3 or $4 and lasts me a long time. If kept in the fridge it lasts for quite some time and have never had issues with the dough not rising.

[tino27]

They are interchangeable in recipes, but not a 1:1 ratio. The problem with fresh yeast is that unless you are baking a lot of bread (as in a bakery), it can be prohibitively expensive when compared to dried yeast (either Active Dry or Instant).

At my supermarket, a 57g block of fresh yeast is roughly $2-$2.49, depending on the day. That will give me roughly 3-4 batches of bread (9-12 loaves overall). At Sam's Club, I can buy 2 one pound hermetically sealed sacks of instant yeast for $4. Because instant yeast is more potent, only 1/3 the amount of fresh yeast is needed.

So, assuming 20 grams of fresh is needed per batch, only 7 grams is needed for instant. 454 grams per pound / 7 grams per batch = 65 batches of bread per pound of yeast.

Plus, you can keep your dry yeast in a sealed container in the fridge for quite a long time (I usually go through a pound of dry yeast in about 9 months or so).

Active Dry doesn't use the same 1/3 conversion that Instant does, but it is close.

As far as quality of the finished product, I've never noticed a difference when switching between the two. As long as I do the proper conversion ratio from one to the other, my recipes have always come out fine.

[paulraphael]

Assuming you figure out the right conversion, the results should be basically identical. It's all the same strain of yeast, and the yeast you put into the recipe is only getting the culture started. That original yeast will be long gone, replaced by its great great great grandchildren, by the time your bread goes in the oven. A biologist would probably have a hard time figuring out if the origin of any of these organisms was a packet of instant yeast or block of fresh.

There's one significant practical difference. Fresh yeast contains a huge percentage of dead yeast organisms. This is one of the reasons you need to use proportionally more of it. In some cases, the quantity of dead yeast you're adding will be high enough that the bread will have a noticeably yeasty flavor. Artisinal bakers generally consider this a flaw, but some people seem to like it.

The same effect can be produced by adding brewers yeast (which is also inactive).

[genarog]

I don't know whether the end product is any different with fresh or dry yeast, but I really like the smell of fresh yeast.

[P1800Girl]

I don't know whether the end product is any different with fresh or dry yeast, but I really like the smell of fresh yeast.

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Oh my! The smell is fabulicious! One whiff and I'm on a trip straight back to Europe and my grandmother's kitchen!

I freeze a block of it and use it occasionally to fire up a sourdough recipe. I just used some yesterday on a batch of sourdough I will be making crusty German rolls with. Dough is in the fridge, but smells divine already.

Someone mentioned the cost being high, but I get it at a restaurant supply store and it is very reasonable. A 'brick' of it, which is about the size (volume wise) of a pound of butter is about $.79. If you don't have one near you, make friends with a pizzeria owner who makes his own dough. I'll bet dollars to dough, he is using fresh yeast.

-sabine

[Isabelle Prescott]

I don't know whether the end product is any different with fresh or dry yeast, but I really like the smell of fresh yeast.

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Oh my! The smell is fabulicious! One whiff and I'm on a trip straight back to Europe and my grandmother's kitchen!

I freeze a block of it and use it occasionally to fire up a sourdough recipe. I just used some yesterday on a batch of sourdough I will be making crusty German rolls with. Dough is in the fridge, but smells divine already.

Someone mentioned the cost being high, but I get it at a restaurant supply store and it is very reasonable. A 'brick' of it, which is about the size (volume wise) of a pound of butter is about $.79. If you don't have one near you, make friends with a pizzeria owner who makes his own dough. I'll bet dollars to dough, he is using fresh yeast.

-sabine

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Someone gave me a brick she buys in a restaurant supply store and told me to cut it into1/3 inch sections and freeze them for later use. I made white bread with the chunk I didn't freeze and it rose twice as fast as instant yeast. The bread was delicious.

Normally I bake with my sourdough starter (used La Brea Bakery method with grapes to create) and though it takes a long time... the resulting loaves are more flavorful than when made with yeast.

[K8memphis]

I love fresh yeast for baking. I can tell a difference. I love it. And I can't get it around here either--sniff. I could get it shipped in for overnight $hipping cost$ but no thanks anyway.

[K8memphis]

what's the general consensus (if any) on which is better out of the 2 types of yeast? i'm not sure if it's just hearsay but apparently yeast technology has advanced so far that there's almost no difference. can this rumor be substantiated?

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In baking, "almost no difference" can be vast huh.

[chef koo]

if there's no noticeable difference in the finished product, then why do so many commercial bakers use fresh yeast?

[tino27]

if there's no noticeable difference in the finished product, then why do so many commercial bakers use fresh yeast?

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My guess would be tradition. The last head baker I worked for used only fresh yeast (while I prefer instant in my personal breads). When I asked him about this preference, he certainly knew about other types besides fresh, but that was what they taught at his culinary school and that was what all the bread formulas were already written to use, so that's what we used.

Isabelle -- Are you sure you used the right ratio from fresh:instant yeast in your white bread? Could there also have been a temperature or humidity difference between the two batches? I am often baking at someone else's house and many times the only yeast available is something other than instant. As long as I convert the amounts correctly, the breads always take similar amounts of time. When I teach bread classes, I always bring all three types to class to demonstrate to students that they shouldn't feel locked in to only one type of yeast if others are available.

[dougal]

... why do so many commercial bakers use fresh yeast?

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The answer is likely to be any, some or all of the following reasons:

- Because its cheaper. (Barely these days, but it used to be significantly cheaper) And commercial bakers do use a lot of it

- Because its what they've always used

- Because the business has always had proper cool and humid storage facilities to minimise its deterioration over a few days of storage

- Because they use lots of yeast, and so can comfortably use all the delivery well within its short shelf life. Therefore short shelf life is no major disadvantage to them.

- Because they dislike the characteristics of Active Dry.

- Because they misunderstand the Instants. These might be a touch more expensive than Fresh, likely were not in wide use when they were trained, and have been woefully mis-sold, particularly in the USA.

- Because they think dried yeasts are 'full of additives'

- Because "fresh" must mean better, right?

- Because they believe dried yeast "is for home cooks"

- Or because they think there is only ONE type of "dried" yeast, (and they don't like it)

"Fresh" yeast is the factory-made processed product of the late 1800's. Hence its "traditional".

It has a shelf life measured in days.

Its about 70% water.

Freezing it kills many of the yeast cells. Dead yeast cells do matter, see below.

Damaging the product is why "fresh" yeast is not sold from the freezer cabinet in stores.

Active Dry is the processed product of the 1940's. It was designed for the military - to provide a shelf life measured in years, if not decades.

It is as much of a gourmet product as any other military ration. Despite that, its conveniently long storage life made it a domestic alternative to a product that spoiled quickly.

Its actually "Actively Dried" - dried by heating.

It has almost no water, so you use less weight of the product to get the right amount of live yeast.

But many/most of its yeast cells are actually dead. As a result of the heat-drying.

So you need to use more (total) yeast cells to get the same number of live ones to do the work.

This gives a distinct "yeasty" taste to the bread. Which some people do actually prefer.

The dead yeast also acts as a "dough conditioner". (You can buy "deactivated" yeast specifically for use as a conditioner.) Its function is to make the dough weaker, smoother and more stretchy, (more "extensible"). Some bakers like that. Its easier for automated shaping. Especially with 'strong' North American flours.

Personally, I think weak, very extensible dough is what I want for pizza, rather than bread.

But, again personally, I don't like the strong yeast taste, even in pizza.

Because the grains have a protective covering of dead yeast cells, the stuff has to be rehydrated carefully - typically 10 minutes or more in warm water.

Frozen, or slightly stale, 'fresh' yeast has plenty of dead cells.

So it then works rather like Active Dry, with more extensibility and more yeast taste.

The processed product of the 1970's is Instant Mix yeast (though the term I prefer is "Easyblend").

Its vacuum dried, at low temperature.

This is much less damaging to the yeast cells than heat drying.

The first misunderstanding is about speed - its NOT faster. The only thing 'instant' is the availability -- you don't need to prepare by rehydrating the yeast with warm water for 10 minutes -- it is "instantly available" without the 10 minute wait.

Its got much less dead yeast than Active Dry. And again no water.

So, if you use the same weight of Easyblend as Active Dry, then you will be putting in more live yeast cells. This is just like putting in a larger quantity of 'fresh' yeast - which gives quicker rising, so less bread taste, and more taste of yeast, because there's more yeast in the product.

So - second misunderstanding - do NOT use the same quantity as of Active Dry - use LESS, like 25% less by weight than of Active Dry.

Its not as 'bulletproof' in storage as Active Dry, but treated well, it stores for ages.

Third misunderstanding - in storage, what it needs protection from is humidity, more than temperature. Keep it sealed (once open, in a 'small' sealed container) and cool does no harm. Freezing really isn't helpful. Vac packing however, is great.

The fourth misunderstanding is to confuse "Easyblend" yeasts with special "Bread Machine" yeasts. And wooo, the manufacturers and their marketing departments deserve the blame for this one, big time.

Special yeast products are produced specifically to assist the automated processing in bread machines.

These are derived from Easyblend yeasts but have an additional cocktail of "improvers" derived from industrial breadmaking.

While they undoubtedly can 'help' a bread machine loaf to more closely resemble a supermarket loaf, I and many others would rather not use them. I want my bread to be better than the supermarket's.

The problem is that the marketing (product names, etc) of Bread Machine and Easyblend yeasts is completely unhelpful in distinguishing between them.

The word "rapid" might be applicable to Bread Machine yeast/improver cocktails - but it is misapplied regularly to Easyblend - which is only more rapid than anything else if you use it to excess. But then salesmen want to shift product, and you'll shift more if you tell people to use an excessive quantity. Doh! Pack instructions in the USA can be guilty of this.

You can use Easyblend perfectly well in a machine, but you miss out on all the 'improvements'. Hence the marketing confusion.

To tell the difference from the pack, you really do have to look closely at the small print ingredients listing on the label.

An Easyblend yeast will only have a trace (normally way less than 1% of the yeast's tiny weight) of soapy stuff, to help it rehydrate. This will typically be a "Stearate". It might be described as an emulsifier. Honestly, its nothing to fuss about if you use detergents in your home, especially those designed for dishwashers. You might find a trace of Vitamin C as well, sometimes called by one of its chemical names, Ascorbate or Ascorbic Acid. There's way too little to do you any good, and anyway it is destroyed in the oven. But it is good for dough, (it protects the yeast from chlorine/chloramide in your water, and also strengthens the dough), and, hey, its less harmful to you than Orange Juice.

However, anything else, enzymes, stabilisers, preservatives, whatever - indicates a Bread Machine yeast. And if you are not using such a machine, there's no need for them.

Different manufacturers have differing strains of yeast. One 'fresh' product is unlikely to be identical to another.

And manufacturers may choose to vary the strain they use in different preparations.

But that's about that manufacturer's specific product, rather than the generality.

And, yes, there are special strains available, for special purposes. But few of them are available retail (especially in the UK). If you don't know about osmotolerant yeasts, you probably don't need to worry about them!

For domestic manual bread baking, an Easyblend yeast is the best product.

In taste terms, its way better than Active Dry, most authorities (including Prof Calvel) say it produces results equivalent to, if not better than, (fresh not stale) 'fresh' yeast.

Its got no storage problem. It keeps for months (at least).

And its more convenient to use. Just add it straight into the flour.

When one takes wastage into account, its likely cheaper, per loaf, domestically, than 'fresh'.

What's not to like?

[paulraphael]

Peter Reinhart shocked quite a few traditionalists when he wrote all the artisinal recipes in the Breadbaker's Apprentice for instant yeast. I wrote to him about this and his reply included a fair amount of what dougal said.

He also explained that artisan bread baking, in his view, is about getting as much flavor as possible out of the wheat (or in the case of naturally fermented breads, the bacterial cultures). Anything else that might effect the flavor, like gobs of dead yeast, is to be avoided. So instant is a logical choice.

He also encourages people to make identical loaves with the three kinds of yeast (portioned accordingly) to compare for themselves.

Edited March 17, 2009 by paulraphael (log)

[cmflick]

I seem to remember reading that fresh yeast is more osmotolerant, i.e., better for sweet doughs, than active dry yeast or instant yeast. I think that I saw this in Maggie Glezer's Artisan Baking Across America. Anyway, there is also osmotolerant dry yeast that is good for sweet doughs. The only brand that I know of is SAF Gold.

[slkinsey]

Yea. I've always believed that if you're going to use commercial yeast, the smaller the amount you use, the better the result.