Starter Ingredients: Cheap White Sugar + Nutrients?

[Natethebrewer]

I thought the single cell thing was myth, go figure.
I prefer to just use a portion of the yeast cake from my primary (2nd generation yeast and all) instead of starting starters

 

[Brewitt]

I thought the single cell thing was myth, go figure.
I prefer to just use a portion of the yeast cake from my primary (2nd generation yeast and all) instead of starting starters

Good Call! High density of yeast, pre grown on maltose with all the right conditions.

 

[emjay]

A single cell of yeast CAN lead to it being fermented out eventually, but not usually. Same reason we don't need to sterilize everything, and just sanitize - a few lacto cells aren't going to turn our beers sour.

 

[Natethebrewer]

So much easier and cheaper that way

 

[Bierliebhaber]

"Problems arise only if the nitrogen composition is low. This occurs only if a cheap or poor quality malt extract is used or if there are a large amount of adjuncts added. In terms of propagation, the closer the starter media is to the fermentation wort the better."

A quote from this excellent and informative article: http://www.maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

 

[gmcastil]

I guess this is another thing I have to try first hand. I'm not sure if I agree with the rumor that training yeast to simple sugar is making them fat and lazy.

In order to break down polysaccharides like sucrose, maltose, etc. microorganisms synthesize enzymes. If yeast are grown in a medium that does not include a particular sugar, they won't synthesize the enzymes required for metabolizing those sugars. It has nothing to do with yeast growing fat and lazy - it's related to the regulation of gene transcription and protein synthesis.

There are a lot of things in the homebrewing community which are taken as gospel without any evidence but proper yeast pitching rates and yeast cultivation are pretty well understood at this point. That's a big part of what makes homebrewing a lot easier today than it would have been 15-20 years ago.

Also, considering that DME is about the same price as sucrose, I don't see the reason for wanting to make a yeast starter without extract.

Edit: An analogous example can be found in E. coli. There are several proteins which are required for E. coli to metabolize lactose, another simple disaccharide. The production of those enzymes is regulated by lactose itself. The presence of lactose signals the cell to begin transcription of the transporter which actually allows lactose into the cell as well as the enzyme which cleaves the ether linkage holding the two sugars together. This particular system is very well understood and shows up all over the place in microbiology - look up the "lac operon" and you can read some fairly basic stuff on how it all works.

Now lets talk mutations - there are about a billion yeast cells in a vial. Their genomes are not all identical and regulation of the biochemical machinery needed for fermentation is not the same. Some are more / less capable than others of metabolizing the sugars present in wort. Some may not even have the capacity to digest maltose (this happens in humans with lactose - lactose intolerant folks still have the genetic information to synthesize the lactase enzyme, but the cells in their intestine have down regulated the production of it). So, if you grow up a yeast culture that only has maltose as a substrate (e.g., a starter with DME or a low-gravity wort), you are automatically selecting for the ones which are ultimately best suited to ferment your wort. Only cells which can metabolize maltose will be able to proliferate and make it into your wort.

 

[gmcastil]

According to my research (googling), it points to something called the Crabtree effect; something what happens in high concentrations of glucose will cause yeast to stop growing and instead turn attention to producing ethanol. But apparently, if the gravity is low enough, this shouldn't be a problem. Still searching for more information.

This is absolutely true, which is why, even for a high gravity beer, the starter wort is kept at a low gravity. I wasn't aware it was called the Crabtree effect, but it makes sense if you look at it from the standpoint of natural selection.

 

[signpost]

Edit: An analogous example can be found in E. coli. There are several proteins which are required for E. coli to metabolize lactose, another simple disaccharide. The production of those enzymes is regulated by lactose itself. The presence of lactose signals the cell to begin transcription of the transporter which actually allows lactose into the cell as well as the enzyme which cleaves the ether linkage holding the two sugars together. This particular system is very well understood and shows up all over the place in microbiology - look up the "lac operon" and you can read some fairly basic stuff on how it all works.

Now lets talk mutations - there are about a billion yeast cells in a vial. Their genomes are not all identical and regulation of the biochemical machinery needed for fermentation is not the same. Some are more / less capable than others of metabolizing the sugars present in wort. Some may not even have the capacity to digest maltose (this happens in humans with lactose - lactose intolerant folks still have the genetic information to synthesize the lactase enzyme, but the cells in their intestine have down regulated the production of it). So, if you grow up a yeast culture that only has maltose as a substrate (e.g., a starter with DME or a low-gravity wort), you are automatically selecting for the ones which are ultimately best suited to ferment your wort. Only cells which can metabolize maltose will be able to proliferate and make it into your wort.

This explanation is awesome. Thanks. So this makes it seem to be much more of a "survival of the fittest" type thing. Basically, the yeast that aren't fit for the desired job (fermenting beer) aren't given an opportunity to propogate if the starter is malt-based. Do I kind of have that right?

 

[gmcastil]

This explanation is awesome. Thanks. So this makes it seem to be much more of a "survival of the fittest" type thing. Basically, the yeast that aren't fit for the desired job (fermenting beer) aren't given an opportunity to propogate if the starter is malt-based. Do I kind of have that right?

Yeah, that's more or less it. To be sure, there is more to it and I don't claim to be an expert on yeast, but you basically have it right.

 

[emjay]

This explanation is awesome. Thanks. So this makes it seem to be much more of a "survival of the fittest" type thing. Basically, the yeast that aren't fit for the desired job (fermenting beer) aren't given an opportunity to propogate if the starter is malt-based. Do I kind of have that right?

That's half the story. At one point that was how I understood it too, as it's easy enough to come to this conclusion simply with a bit of reasoning. But there's more going on... even the original cells that are pitched into the maltose-lacking medium (as opposed to being a "descendant" of these cells) can LOSE the ability to produce the necessary enzymes (as he actually touched on above), so it's more than simply a result of natural selection, though that does indeed happen as well.

 

[gmcastil]

That's half the story. At one point that was how I understood it too, as it's easy enough to come to this conclusion simply with a bit of reasoning. But there's more going on... even the original cells that are pitched into the maltose-lacking medium (as opposed to being a "descendant" of these cells) can LOSE the ability to produce the necessary enzymes (as he actually touched on above), so it's more than simply a result of natural selection, though that does indeed happen as well.

Right. It's not just a matter of natural selection - yeast that are raised in the absence of maltose can lose the capacity to produce the necessary enzymes, probably due to altered gene expression.

 

[Brewitt]

You know the old adage, use it or lose it. This isn't really selection but lack thereof. If we don't demand something of a yeast cell, next time we ask them for it it might not be there. The selection happens when we ask for it again. I know its a dirty word in some circles but this is how evolution works. Lots of different things lead to changes in traits over time. We see it faster in yeast because the generation time is 2-3 hours instead of 20 years.

The point was made in an earlier post that this doesn't have to happen through permanent mutation but cells can just get used to one growth condition or another. If they are used to one it can take them longer than usual to get going on another. My understanding is that in the case of maltose fermentation this shouldn't be an issue, induction of the enzymes is pretty fast. But I don't know about the rest of the nutrient conditions in wort.

Another point, if you start out with many cells than the probability of a mutant taking over a population due to a growth advantage is small, if you start with just one cell or a few, it becomes much greater.

 

[Brewitt]

I seem to be flogging a dead horse. ;-)

 

[overdbus]

More like singing to the choir.

 

[gmcastil]

I ran across this article earlier today on diacetyl production in beer.

http://morebeer.com/brewingtechniques/library/backissues/issue1.2/fix.html

The author talks about a lot of different causes for it, but one of them jumped out at me, so I wanted to resurrect this thread in case anyone else was interested. The entire article is a great read, but it may be a little hard to understand for readers without a biochemistry or organic background. I've tried to summarize it here:

https://www.homebrewtalk.com/f128/c...protein-energy-298164/index2.html#post4228721

The major point which pertains to our discussion here was his experiments with yeast grown on dextrose-sucrose rich media. As one would expect, the culture growth was very rapid, but the yeast performed unacceptably during fermentation and demonstrated a poor uptake of valine which led to large increases in diacetyl in the finished product.

Hope this helps.

 

[iambeer]

I don't keep yeast for long. Never more than two beers. After one beer, I keep the 'cleaned' slurry because it's easy and fine. After thinking long and hard about this, I decided to go with this method:

As far as starters from the original yeast sample I purchase, I don't see any harm in feeding it simple sugar. I have began doing this, and it seems fine.. It seems to multiply at ease. Like another poster said, it apparently does not mutate swiftly into a yeast that will no longer be able to process maltose. That is bogus unless you keep generations of the same yeast.

I am not worried about the long term effects of yeast mutation because I will eventually buy a new sample every so and so months.

 

[gmcastil]

I don't see any harm in feeding it simple sugar. I have began doing this, and it seems fine.. It seems to multiply at ease.

You should read that article I linked to - it specifically mentions making starters with sucrose. It's not about how much multiplication you get - it's about the health of the cells. I'm just surprised that a guy that wanted real primary information is now willing to ignore it because "it seems fine".

Part of homebrewing is the freedom to do what you like. I wouldn't recommend making starters from table sugar. None of the research into brewing science I've seen supports that idea either and there is plenty that says it's unwise, produces off-flavors, and in general is a bad practice. But, you're free to do what you like.

 

[Justintoxicated]

So Basically, using table sugar does not get the yeasts creative juices flowing? get it?

 

[gmcastil]

So Basically, using table sugar does not get the yeasts creative juices flowing? get it?

Not sure what you mean, but using table sugar as a medium for growing a yeast starter is a bad idea and does not yield the same quality of finished product. I'm not sure why anyone would choose to use sucrose to make a yeast starter in light of that fact.

 

[kapbrew13]

If an athlete is runner, why would he train in a swimming pool? Olympic analogy (??)
Yes he will build strength but in mostly the wrong areas.
Yes it helps them become stronger.
Same thing. Grow you yeast in a similar environment (gravity) as your final brew.
I start at 1.040 , decant, and up it to 1.049 depending on gravity of my brew.

If you want to use simple sugars. Go ahead. If you like your product, that's what counts.
Good luck.

 

[Bierliebhaber]

If an athlete is runner, why would he train in a swimming pool? Olympic analogy (??)
Yes he will build strength but in mostly the wrong areas.
Yes it helps them become stronger.
Same thing. Grow you yeast in a similar environment (gravity) as your final brew.
I start at 1.040 , decant, and up it to 1.049 depending on gravity of my brew.

If you want to use simple sugars. Go ahead. If you like your product, that's what counts.
Good luck.

I believe the analogy would be more akin to cigarettes and alcohol vs pre-natal vitamins...a baby will come out either way, but how will it function?

 

[DrummerBoySeth]

I believe the analogy would be more akin to cigarettes and alcohol vs pre-natal vitamins...a baby will come out either way, but how will it function?

The analogy I prefer is giving a child dessert before making him eat his vegetables. When you give the yeast simple sugars like sucrose first (dessert) then they get all fat and happy on all that sugar and do not want to eat their maltose (vegetables)

However, if you make the child eat the broccoli first, then they will still want the ice cream! It just does not work the other way around. I do not know many children who are willing to eat broccoli after feasting on ice cream.

 

[kapbrew13]

I believe the analogy would be more akin to cigarettes and alcohol vs pre-natal vitamins...a baby will come out either way, but how will it function?

Kind of disturbing. Like the pictures on the side of the cig boxes?

 

[kapbrew13]

The analogy I prefer is giving a child dessert before making him eat his vegetables. When you give the yeast simple sugars like sucrose first (dessert) then they get all fat and happy on all that sugar and do not want to eat their maltose (vegetables)

However, if you make the child eat the broccoli first, then they will still want the ice cream! It just does not work the other way around. I do not know many children who are willing to eat broccoli after feasting on ice cream.

Chocolate covered broccoli? YUM!