Any reason to use malt extract instead of other sugar for yeast starters?

[GNBrews]

If I plan to crash cool and pitch only the yeast cake from a starter, is there any significant reason why I can't use a fermentable sugar other than malt extract? For example, corn syrup or dextrose? With the price of extracts being so high lately, I'd rather spend the money on my grain bill.

 

[SwampassJ]

Everything I've seen says it has to do with the nutrients in the extract vs those not found in table sugar being essential in healthy yeast growth.

Personally I've never tried a sugar only starter and everytime I forget to split my vial or tube in two to see if it works as well. I have used it to compensate for not having enough DME to get to a decent OG on the starter and cut it something like 33% sugar and 67%ish DME and it turned out fine. Also I know the mead makers and wine makers in this forum use nutrient additions, so I guess it could be done with the nutrient additions.

 

[dannypo]

You really shouldn't use simple sugars for starters. Here is a simplified explanation.

Yeast require a certain enzyme in order to ferment maltose and maltotriose (the two most common sugars in wort). If the yeast ferment a high concentration of simple sugars they stop producing this enzyme. Once they stop they tend to be unable to begin synthesize it again. You end up with very under attenuated beer in the end.

Like I said, I simplified it a bit because I didn't feel like looking the specifics. But that's the general idea.

 

[elkdog]

You really shouldn't use simple sugars for starters. Here is a simplified explanation.

Yeast require a certain enzyme in order to ferment maltose and maltotriose (the two most common sugars in wort). If the yeast ferment a high concentration of simple sugars they stop producing this enzyme. Once they stop they tend to be unable to begin synthesize it again. You end up with very under attenuated beer in the end.

Like I said, I simplified it a bit because I didn't feel like looking the specifics. But that's the general idea.

+1

You need your yeast to be trained to eat maltose and maltotriose, not just sucrose, which is simpler and therefore easier for them to ferment.

 

[bja]

Yeast require a certain enzyme in order to ferment maltose and maltotriose (the two most common sugars in wort). If the yeast ferment a high concentration of simple sugars they stop producing this enzyme. Once they stop they tend to be unable to begin synthesize it again. You end up with very under attenuated beer in the end.

Of course this doesn't happen overnight (if it happens at all). It takes many many generations. It's not like they flip a switch and turn off that enzyme.

 

[theredben]

Moral of the story is that if you are concerned about how much money you are spending on DME for starters, just make a smaller one.

I have also started doing small 5 lb 2-row mashes, and canning that for starters. Works great and is super cheap.

 

[SwampassJ]

Moral of the story is that if you are concerned about how much money you are spending on DME for starters, just make a smaller one.

I have also started doing small 5 lb 2-row mashes, and canning that for starters. Works great and is super cheap.

Or if you're feeling a little adventurous you could build a stir plate and buy a stir bar. You can get away with much smaller starters this way.

If you want to make it easier a flask can be boiled in and cooled down in vs cooling the starter in the pot before pouring into the starter vessel. Just a few initial cost bumps and then you're golden.

 

[dannypo]

Of course this doesn't happen overnight (if it happens at all). It takes many many generations. It's not like they flip a switch and turn off that enzyme.

Actually this can occur very quickly. In just a couple generations. And since in an average fermentation there are more than two generations the inability to ferment more complex sugars can show up in the time from pitching into the starter and fermentation completion.

 

[bja]

Actually this can occur very quickly. In just a couple generations. And since in an average fermentation there are more than two generations the inability to ferment more complex sugars can show up in the time from pitching into the starter and fermentation completion.

You got proof of that?

I use any extra runnings from the mash to make starter wort and almost always add sugar to raise the gravity. I've never experienced any problems with under attenuation.

I occasionally make starters for 10 gallon brews from a single slant, which means stepping up 4-5 times. So I have at least 5-6 generations and still have never had a problem.

 

[MachineShopBrewing]

You got proof of that?

Yep, check out Yeast, a Practical Guide to Fermentation by Chris White(White Labs) and Jamil Zainasheff.

It happens very quickly. If you made a starter with sugar, your yeast would have serious trouble fermenting maltose afterward.

 

[bja]

Yep, check out Yeast, a Practical Guide to Fermentation by Chris White(White Labs) and Jamil Zainasheff.

It happens very quickly. If you made a starter with sugar, your yeast would have serious trouble fermenting maltose afterward.

Is that quoted from the book?

I never said you should use 100% sugar which I assume you are referring to . I said I add some to increase gravity of the starter wort. It ends up being ~50%.

 

[MachineShopBrewing]

I've never tried it, but I would assume that 50/50 would be ok.

 

[theredben]

I've never tried it, but I would assume that 50/50 would be ok.

Reading this thread has got my mind working. I have 10 750mL batches of wort in canning jars cooling outside right now. My plan is as follows:

5 different recipes, 2 yeasts (1968 and 1056), gives me 10 jars of 1.030 wort.

1: DME
2: 50/50 DME and Sucrose
3: 50/50 DME and Dextrose
4: Sucrose
5: Dextrose

I have chosen 1968 and 1056 because it gives a high/low attenuation comparison. I will ferment at room temp and take a FG reading, decant and taste for any defects, then remove 3/4 of resulting yeast and fill up again with corresponding solution. This will be repeated for 5 sucessive fermentations or until the results are obvious. I will end up posting this in the Brew Science forum.

 

[GNBrews]

Reading this thread has got my mind working. I have 10 750mL batches of wort in canning jars cooling outside right now. My plan is as follows:

5 different recipes, 2 yeasts (1968 and 1056), gives me 10 jars of 1.030 wort.

1: DME
2: 50/50 DME and Sucrose
3: 50/50 DME and Dextrose
4: Sucrose
5: Dextrose

I have chosen 1968 and 1056 because it gives a high/low attenuation comparison. I will ferment at room temp and take a FG reading, decant and taste for any defects, then remove 3/4 of resulting yeast and fill up again with corresponding solution. This will be repeated for 5 successive fermentations or until the results are obvious. I will end up posting this in the Brew Science forum.

Excellent idea! Are you going to use the yeast produced from the initial starters (1-5) to ferment malt extract in the subsequent tests?

 

[theredben]

I will run these condition for 4-5 generations, or until the results seem obvious, then do a large batch of real wort.

 

[GNBrews]

So, the #2 condition (50/50 DME and Sucrose) will be fermented for 4-5 generations (or until you get a stuck fermentation) on the same substrate (50/50 DME and Sucrose)?