Yeast aeration? Danstar Nottingham data sheet says not necessary.

[Silver_Is_Money]

Per the data sheet for Danstar Nottingham dry yeast, the package contains an adequate reservoir of carbohydrates and fatty acids, and it is therefore unnecessary to aerate the wort. Should I trust this direct from the manufacturer advice?

 

[STMF]

Yes, if you pitch the right amount of yeast and not plan to reuse the yeast.

Note that the data sheet says that 100g/100hl (1g/liter) will give you 5-10 million cells per milliliter. That equals to about 100-200 billion cells per 5 gallons of wort. Also, they state a 25% decrease of living cells per year if stored at 8 degrees Celsius (46F) and 50% decrease per year at 22C (72F).

My point is that you can not just pick out one thing (Rehydration not needed) without taking the rest of information into consideration.

If the package is stored in room temperature at a LHBS for a year, you could (according to the datasheet) pitch as low as 50 billion cells per 5 gallon. At that level, aeration and yeast nutrition would probably be necessary raise your chances for a healthy fermentation.

 

[AZCoolerBrewer]

One of the benefits of using dry yeast is that aeration isn't such a big deal. There is also a ton of yeast in a small package. I have only used liquid once and am ambivalent about the viability, but dry yeast, if you look around there are a ton of options. If you calculate your time and the expense of supplies that go into starters, dry yeast has great value for quantity and quality. BTW Nottingham is an absolute monster yeast and will blow through big and little beers like nobody's business.

 

[MaryB]

I use a lot of Notty. I basically rehydrate in a liter of wort and build a mini starter overnight. But I am pushing beer to drinkable in 14 days at times too... and that is bottle conditioned! Notty does well with a 4 week primary too because it clears better.

 

[STMF]

I use a lot of Notty. I basically rehydrate in a liter of wort and build a mini starter overnight. But I am pushing beer to drinkable in 14 days at times too... and that is bottle conditioned! Notty does well with a 4 week primary too because it clears better.

I'm not saying that what you do does not work.

But, what you are doing goes against the manufactures, and alot of knowledgeable peoples, recommendation. There are studies that shows that UP TO (some people misunderstand this for ALWAYS) 50% of the cells can die if you rehydrate in wort.

But like I started, if it works for you, just continue. I just wanted to add some additional information.

 

[Silver_Is_Money]

There has been discussion of replacing wort aeration with the simple addition of about 1/5 of a drop of olive oil just prior to pitching. When Danstar states that a pack of Nottingham contains sufficient fatty acids to forego aeration, they must be stating that they have added to the package whatever requisite fatty acid it is that is also present in olive oil, and which the yeast must first fabricate from aerated wort before they can begin the task of converting sugars to alcohol. If this particular fatty acid is already present, the yeast can merrily skip this step, and the brewer can skip adding air to their wort. Air which may lead to the development of off flavors down the road.

 

[STMF]

There has been discussion of replacing wort aeration with the simple addition of about 1/5 of a drop of olive oil just prior to pitching. When Danstar states that a pack of Nottingham contains sufficient fatty acids to forego aeration, they must be stating that they have added to the package whatever requisite fatty acid it is that is also present in olive oil, and which the yeast must first fabricate from aerated wort before they can begin the task of converting sugars to alcohol. If this particular fatty acid is already present, the yeast can merrily skip this step, and the brewer can skip adding air to their wort. Air which may lead to the development of off flavors down the road.

From what I've read the Olive-Oil-Theory is another thing that has been misinterpreted, and passed on, by a lot of homebrewers. That original study was about storing yeast, not during active fermentation. I have not seen any study or experiment that showed that you could implement it successfully during fermentation. Every one that I have seen has shown the opposite.

 

[STMF]

Other than that I agree with what you say about dry yeast manufacturs "packing" the dry yeast with what is needed for fermentation. This is also why they say that if you are going to reuse the yeast, you need to make addition to make sure the yeast is healthy after fermentation.

 

[Silver_Is_Money]

From what I've read the Olive-Oil-Theory is another thing that has been misinterpreted, and passed on, by a lot of homebrewers. That original study was about storing yeast, not during active fermentation. I have not seen any study or experiment that showed that you could implement it successfully during fermentation. Every one that I have seen has shown the opposite.

Is it possible that Lallemand (Danstar, Lalvin) is not giving us good advice, and that we should ignore it? It seems to me that they should know what they are talking about, and if they say we should skip aeration, we should skip aeration.

If olive oil has been disproven, then perhaps the fault lies with the olive oil, and not with the fatty acid that Danstar is including in each package?

 

[STMF]

Is it possible that Lallemand (Danstar, Lalvin) is not giving us good advice, and that we should ignore it? It seems to me that they should know what they are talking about, and if they say we should skip aeration, we should skip aeration.

If olive oil has been disproven, then perhaps the fault lies with the olive oil, and not with the fatty acid that Danstar is including in each package?

I'm pretty sure that the advice they give is good advice. But like I wrote eariler, we can't just pick one thing they say and ignore the others. They depend on eachother. If you underpitch, straight into wort, with a package that has lost viability - not areating will not save you somehow.

About the olive oil, I absolutly agree with you. They make sure that there is enoguh fatty acids, but not by adding olive oil

 

[LBussy]

You will not harm things by aerating your wort and adding yeast - dry or liquid. It is possible that your yeast has become stressed and aerating (or even better, using O2) will benefit things or even be needed.

I look at some of those manufacturing quips as marketing. Sort of like "Scrubbing Bubbles" cleaning your tub without needing to scrub. Nobody wants to scrub, everyone likes a shortcut. Figure out if your product can survive a shortcut and you have a great marketing pull. Yes they are ultimately the experts in their product, but not all directions are intended to produce the best product - some are intended to make it approachable to the lowest common denominator.

As noted, Notty is a great yeast, very forgiving, and you'll probably be fine if you don't aerate. I just don't think it's optimal.

 

[Silver_Is_Money]

I'm pretty sure that the advice they give is good advice. But like I wrote eariler, we can't just pick one thing they say and ignore the others. They depend on eachother. If you underpitch, straight into wort, with a package that has lost viability - not areating will not save you somehow.

About the olive oil, I absolutly agree with you. They make sure that there is enoguh fatty acids, but not by adding olive oil

I always re-hydrate per instructions.

I just read an article about the olive oil experiment. Here are some quotes from the article:

Mr. Hull conducted experiments by adding measured amounts of olive oil to stored yeast 5 hours prior to pitching. (He did not add the olive oil directly to the wort at pitching time.)

Overall, the experimental beers and the controls were very similar — similar enough that the brewery released the final experimental batches to the public. Head retention times in the experimental beers were only slightly less than that seen in controls. Fermentation times were slightly longer, but the differences between the experimental and control groups shrunk as the amount of olive oil increased. And, the beers made with olive oil attenuated as well as the control beers. Ester production was greater in the experimental beers (and remember that ester production increases as wort aeration decreases), but not to the degree that the tasting panel thought it was outside of the brand’s specifications. In fact, the tasting panel preferred the olive oil beers to the controls. And finally, when the tasting panel compared beer samples that had been aged warm for three weeks, they detected less oxidation in the olive oil beers than the aerated beers. In short, Hull’s four experiments supported the idea that olive oil could be used as a replacement for aeration, increasing the flavor stability of a beer — at least in the case of average-strength ales.

http://byo.com/bock/item/1206-olive-oil-aeration

My initial presumption that oxidation via aeration is detrimental down the road seems to have been affirmed.

 

[Pappers_]

What LBussy said ^^^^^ While it may not be neccesary with dry yeast, its a good practice and certainly helps. I aerate with O2 and a wand every batch, dry or liquid yeast.

 

[Silver_Is_Money]

I presume that it is the increase in esters that the tasting panel preferred in the un-areated samples, as well as the reduced oxidation. A bit more esters from Nottingham might help push it more towards S-04 in flavor I would think.

 

[MaryB]

That makes zero sense. Does 50% of a smack pack die in wort? Both are yeast, both are alive... if I pitch straight into the fermenter do 50% say "OH NO WORT" and die? 18-24 hours makes sure I have viable yeast, boosts the numbers some. I am not doing fancy multi step days long starters!

I'm not saying that what you do does not work.

But, what you are doing goes against the manufactures, and alot of knowledgeable peoples, recommendation. There are studies that shows that UP TO (some people misunderstand this for ALWAYS) 50% of the cells can die if you rehydrate in wort.

But like I started, if it works for you, just continue. I just wanted to add some additional information.

 

[RM-MN]

That makes zero sense. Does 50% of a smack pack die in wort? Both are yeast, both are alive... if I pitch straight into the fermenter do 50% say "OH NO WORT" and die? 18-24 hours makes sure I have viable yeast, boosts the numbers some. I am not doing fancy multi step days long starters!

A smack pack contains living yeast cells and pitching into wort doesn't hurt that. It's the dry yeast where it hurts. Those yeast cells have gone through dehydration and when woken up they begin to swell and become active. However, they have difficulty regulating the intake of the wort which can kill them. Instead, use tap water or spring water to rehydrate them. Even using distilled water can be detrimental.

Now with all that behind, the actual number of yeast cells needed to make the best beer has been researched and calculated. However, the difference between getting just the right amount and being way under or over is a little harder to pin down. We do know that a massive overpitch can lead to a drier finish to the beer and a big underpicth can lead to some off flavors but anywhere in between those extremes will lead to acceptable beer for most palates.

 

[Silver_Is_Money]

That makes zero sense. Does 50% of a smack pack die in wort? Both are yeast, both are alive... if I pitch straight into the fermenter do 50% say "OH NO WORT" and die? 18-24 hours makes sure I have viable yeast, boosts the numbers some. I am not doing fancy multi step days long starters!

I believe that the science behind this (with respect to dry yeast specifically) indicates that the cell wall is effectively the life regulator of the yeast, being that it must determine when to admit sugars, and when to expel waste products (including CO2). In the dry and unrehydrated state the cell walls of the yeast are highly compromised, and they must be wetted before they can resume their proper orderly function and duties. They can be overwhelmed by sugar and killed off before this point, so the manufacturers recommendation is often to rehydrate, and some dry yeast instructions indicate specifically that this should never be done directly into wort. If you (and many others, with 'you' in my posts being generic) are getting away with pitching dry yeast directly into wort (be it into a starter or the full batch) you are lucky enough to experience that some quantity of yeast have survived the literal torture you just put them through. You have however unduly and unnecessarily stressed them, and this can sometimes alter their flavor profile. So the next time you blame the yeast for making off flavored beer, reflect back upon your procedure.

So the bottom line is that whereas aeration is not necessary (for some dry yeasts at least, those being the ones for which the fatty acid that they must first generate in the presence of air before moving on to sugar to alcohol conversion, has already been thoughtfully provided) ), rehydration per instructions is still a good practice.

 

[guindilla]

You will not harm things by aerating your wort and adding yeast - dry or liquid. It is possible that your yeast has become stressed and aerating (or even better, using O2) will benefit things or even be needed.

I was recently in a talk made by one of Fermentis representatives on exactly this subject.

He made very clear that we should not oxygenate. He even hinted - well, actually said it quite plainly - that oxydation off-flavours found in many homebrewed beers came from oxygenating the wort. Indeed, as this step was not necessary, the yeast did not consume the oxygen present in the wort, which ended up oxydizing the beer.

I'm not claiming this is the ultimate truth, but worth considering IMHO.

Cheers.

 

[LBussy]

I was recently in a talk made by one of Fermentis representatives on exactly this subject.

He made very clear that we should not oxygenate. He even hinted - well, actually said it quite plainly - that oxydation off-flavours found in many homebrewed beers came from oxygenating the wort. Indeed, as this step was not necessary, the yeast did not consume the oxygen present in the wort, which ended up oxydizing the beer.

I'm not claiming this is the ultimate truth, but worth considering IMHO.

Cheers.

I've heard this. I have a couple issues with it.

One: We have no real tests to prove it. I'd like to see the test results because without them it's still opinion/conjecture. Yes, even from them. They should know better than to present something like this without the proof.

Two: Yeast will preferentially consume oxygen even when "sufficient" sterols are present. Not only will the yeast consume the oxygen but studies show it still improves fermentation:

[T]he addition of oxygen during the stationary phase in a medium containing excess ergosterol and oleic acid increased the specific fermentation rate, increased cell viability, and shortened the fermentation period.

Reference:
Rosenfeld, E., Beauvoit, B., Blondin, B., & Salmon, J. (2003, January). Oxygen Consumption by Anaerobic Saccharomyces cerevisiae under Enological Conditions: Effect on Fermentation Kinetics. Applied and Environmental Biology, 69(1), 113-121. doi:10.1128/AEM.69.1.113-121.2003

This is not new science. The referenced article is from 2003 and studies date back to Pasteur in 1857. He proved that yeast growth increases under aerobic conditions and that fermentation will not occur in earnest until all of the oxygen is consumed.

Reference: Krebs, Hans (1972). "The Pasteur effect and the relations between respiration and fermentation". Essays in Biochemistry (8): 1–34.

Now does this respiration have an impact on the by-products present in our beer? That's a test I would like to see. Good would be a double-blind study fermenting a split batch of wort with the same yeast, oxygenating one sample and attempting to limit aeration on the other. Better would be laboratory tests showing any differences in the fermented product.

So, science tells us that oxygenating wort is good for the yeast. Conversely a couple of scientists (with a vested interest in proving the "simplicity" of using their yeast) tell us the opposite. They are arguing with Pasteur and a body of knowledge that is considerable and demonstrable.

Because of the science, my experience as a brewer, and as a BJCP judge, I oxygenate all of my wort and recommend it to everyone*. Nobody can prove to me that it is a bad thing, while evidence exists to tell me there is a benefit.

*There may be a reason to create conditions under which yeast will perform in a very specific manner. Helles and various Weizen recipes come to mind. In these cases, under-aerating the wort may be desirable.

We have this argument weekly it seems. If you are looking for a reason not to aerate your wort, you will find support for that here in this forum. If you are looking for a reason to oxygenate your wort, you will find that in the science supporting our craft.

 

[mongoose33]

A smack pack contains living yeast cells and pitching into wort doesn't hurt that. It's the dry yeast where it hurts. Those yeast cells have gone through dehydration and when woken up they begin to swell and become active. However, they have difficulty regulating the intake of the wort which can kill them. Instead, use tap water or spring water to rehydrate them. Even using distilled water can be detrimental.

Not being argumentative here but rather trying to learn something.

I use RO water to rehydrate my yeast, in part because my tap water has chlorine in it. I suppose I could boil some tap water to drive off the chlorine, but it's easier for me to sanitize a pyrex cup, add about a quarter-cup of RO water, boil it in the microwave then allow it to cool before adding dry yeast.

I can't recall ever reading that distilled (or RO) water is detrimental to rehydration, and my rehydrated yeast using RO always takes off quickly. However, that's not using Nottingham.

On the technical data sheet for Fermentis' Safale S-04, the instructions for rehydration say to rehydrate the yeast in at least 10 times the yeast's weight of sterile water or wort. Like so:




BUT, the data sheet for Nottingham does say to NOT use RO water:







What am I missing here? I've read the YEAST book by Chris White and Jamil Zainasheff, and there's nothing in there about rehydration that I can find (of course, White Labs doesn't sell dried yeast, maybe that's why).

What happens if one uses RO water?

 

[LBussy]

What am I missing here? I've read the YEAST book by Chris White and Jamil Zainasheff, and there's nothing in there about rehydration that I can find (of course, White Labs doesn't sell dried yeast, maybe that's why).

I am finding it difficult to locate a primary source for the information - granted I am not trying terribly hard. Here however is a re-post of an email list (HBD) conversation between Dan Listerman and Dr Clayton Cone (of Lallemand I believe?):

The water should be tap water with the normal amount of hardness present. The hardness is essential for good recovery. 250 -500 ppm hardness is ideal. This means that deionized or distilled water should not be used.

Source:
http://hbd.org/hbd/archive/3301.html#3301-4

I recommend reading the whole email via the link above as it covers a number of items we are discussing here. If anyone has the gumption to locate a primary source for his assertions, that would be awesome too.

 

[Silver_Is_Money]

I rehydrate dry yeast in RO water with a wee pinch of gypsum dissolved into it. Works great for me. YMMV

 

[RM-MN]

Not being argumentative here but rather trying to learn something.

I use RO water to rehydrate my yeast, in part because my tap water has chlorine in it. I suppose I could boil some tap water to drive off the chlorine, but it's easier for me to sanitize a pyrex cup, add about a quarter-cup of RO water, boil it in the microwave then allow it to cool before adding dry yeast.

I can't recall ever reading that distilled (or RO) water is detrimental to rehydration, and my rehydrated yeast using RO always takes off quickly. However, that's not using Nottingham.

On the technical data sheet for Fermentis' Safale S-04, the instructions for rehydration say to rehydrate the yeast in at least 10 times the yeast's weight of sterile water or wort. Like so:


View attachment 392389

BUT, the data sheet for Nottingham does say to NOT use RO water:



View attachment 392391



What am I missing here? I've read the YEAST book by Chris White and Jamil Zainasheff, and there's nothing in there about rehydration that I can find (of course, White Labs doesn't sell dried yeast, maybe that's why).

What happens if one uses RO water?

http://www.danstaryeast.com/articles/dry-yeast-rehydration-conditions

 

[rimfire]

I have excellent results with US-05 without aerating. You must rehydrate properly, with boiled filtered tap water (you need the minerals), proper temperature (it varies between 80-99), proper method (let the yeast wake up for 10 minutes then stir gently to avoid stress, wait another 10 and stir and pitch).

Following proper procedures will not kill 50% of the cells - sprinkling on top of your wort will. Also the manufacturer is not packing the yeast with anything (maybe some nutrient), the main thing is that the yeast cell has already been biologically prepped for metabolism and has already undergone the process that needs the oxygen. Therefore it is ready to go without aeration. There is also no reason it cannot be repitched the same as any other healthy yeast cells.

 

[Birdgunner]

Been off the threads for a few years but this one piqued my interest when it came across my inbox.
When I first started I followed every direction, read all the homebrew books and was all about the science behind brewing and knowing what worked and why…fast forward close to a thousand gallons later and other than retaining a handful of basic principles most everything else has been forgotten and instead have focused on simplifying my process to what works and makes it fun and easy, that said I haven’t aerated a wort in years and to take it a step further I stopped hydrating my yeast well over 500 gallons ago, whether it be S-04, S-05, Notty or EC1118 (for those runs that use an additional piece of equipment ) I just sprinkle on top the wort in the fermenter and let it ride. My love is Wheat, so maybe with my ales I just get lucky but I have had the same success with Stouts and even the famed Hopslam clone rocking over 10% (although one can get away with a lot of sins with a stout and I guess that same is true with lots of hops) but I have a friend who is a Cicerone and bjcp that regularly consumes my swill and has never had a critical comment or exposed flaws which serves as my validation that sometimes it is best not to over think and complicate things and just do what works for you, keep it easy.