Imperial A09 Pub yeast starter looks sort of coagulated

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troygarrett33

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I created a yeast starter as usual using A09 for an upcoming stout I'll be brewing in a few days. This is the first time I've used the A09 yeast. I noticed from the beginning that the yeast in the packet looked a little "chunky" or coagulated compared to other yeasts. On the stir plate, it has continued to look that way (about 24 hours in):

A09_starter.jpg


Is this normal for this strain of yeast? I'm wondering if I need to make a trip to the homebrew shop for a replacement?

Thanks for any insight!

-Troy
 

Miraculix

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I created a yeast starter as usual using A09 for an upcoming stout I'll be brewing in a few days. This is the first time I've used the A09 yeast. I noticed from the beginning that the yeast in the packet looked a little "chunky" or coagulated compared to other yeasts. On the stir plate, it has continued to look that way (about 24 hours in):

View attachment 780404

Is this normal for this strain of yeast? I'm wondering if I need to make a trip to the homebrew shop for a replacement?

Thanks for any insight!

-Troy
One of my favourite yeasts btw. As you are obviously new to this beauty of a yeast, let me give you some tips to really get into the greatness of this beauty.

1. Mash low. For me, a hoch kurz mash schedule worked best. 62c for 30 minutes, 72c for 30 minutes, 77 for 15 minutes, all done! This yeast is a low attenuator, you want to give it a wort rich in short chained sugars.

2. Add simple sugars in form of invert sugar. You can easily create this yourself. Get yourself some demerara sugar (or any high quality brown sugar, REAL brown sugar, not the refined and sprayed with molasses type of sugar!!!) and a lemon. While boiling the wort, throw the sugar, a dash of lemon juice and some water into a pot and start simmering and dissolving it, till desired colour is reached, but give it at least twenty minutes to reach full conversion. The more water, the less the colour will change. you can also add some unrefined sugar, to further darken the coulour, but I would start experimenting with that some time later.

Add the mixture to the boil within the last ten minutes or so. Use it at a rate of about 5-15% of the total fermentables. 10% is a solid starting point. Use the plain sugar amount to calculate the percentage.

3. Control the temperature... at least a bit. The first two days are basically the main fermentation, the yeast goes CRAZY within these first two days and then stops rather quickly. Within that time, you really want to make sure that the temperature stays within the yeasts limits ie. better do not go above 21 degrees celsius. 19 degrees would be better.

This yeast can create fusels if you let it ride too high and that would hurt your head.

Just keeping it in a tub full of room temperature or colder water will ensure the safety, this is how I handle this yeast.

4. If you ever want to brew a barley wine with it, pitch PLENTY of yeast, and add some US05 to further upp the attenuation. I am drinking a 1.5 year old barley wine that way right in this moment and boooooyyyy is that one GOOOOOOOD ( here is the link to the thread about it Co-pitching A09 Pub and US 05 - Timing? )
 
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troygarrett33

troygarrett33

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One of my favourite yeasts btw. As you are obviously new to this beauty of a yeast, let me give you some tips to really get into the greatness of this beauty.

1. Mash low. For me, a hoch kurz mash schedule worked best. 62c for 30 minutes, 72c for 30 minutes, 77 for 15 minutes, all done! This yeast is a low attenuator, you want to give it a wort rich in short chained sugars.

2. Add simple sugars in form of invert sugar. You can easily create this yourself. Get yourself some demerara sugar (or any high quality brown sugar, REAL brown sugar, not the refined and sprayed with molasses type of sugar!!!) and a lemon. While boiling the wort, throw the sugar, a dash of lemon juice and some water into a pot and start simmering and dissolving it, till desired colour is reached, but give it at least twenty minutes to reach full conversion. The more water, the less the colour will change. you can also add some unrefined sugar, to further darken the coulour, but I would start experimenting with that some time later.

Add the mixture to the boil within the last ten minutes or so. Use it at a rate of about 5-15% of the total fermentables. 10% is a solid starting point. Use the plain sugar amount to calculate the percentage.

3. Control the temperature... at least a bit. The first two days are basically the main fermentation, the yeast goes CRAZY within these first two days and then stops rather quickly. Within that time, you really want to make sure that the temperature stays within the yeasts limits ie. better do not go above 21 degrees celsius. 19 degrees would be better.

This yeast can create fusels if you let it ride too high and that would hurt your head.

Just keeping it in a tub full of room temperature or colder water will ensure the safety, this is how I handle this yeast.

4. If you ever want to brew a barley wine with it, pitch PLENTY of yeast, and add some US05 to further upp the attenuation. I am drinking a 1.5 year old barley wine that way right in this moment and boooooyyyy is that one GOOOOOOOD ( here is the link to the thread about it Co-pitching A09 Pub and US 05 - Timing? )
Thanks for the tips! I don't have a very good way to do a step mash, so was planning to do a single infusion mash targeting about 149F temp for 60 minutes.

When you say 5-15% fermentables, would that be by weight of the sugar relative to the grain bill weight? I assume so. Is the intent for adding the invert sugar to help the yeast with more simple fermentable sugars?

I am planning to start fermentation at 65-66F and gradually increase to about 68F. Do you recommend I keep it more at the 66F range for the entire fermentation? I have a fermentation chamber where I can control the temp.

Thanks again!
 

DBhomebrew

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Not relative to the grain weight, but its portion of it. 10% sugar means 1lb sugar, 9lbs grain.

More Pub goodness...

 
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troygarrett33

troygarrett33

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Not relative to the grain weight, but its portion of it. 10% sugar means 1lb sugar, 9lbs grain.

More Pub goodness...

Yes, that is what I meant by "relative". As a percentage of the grain bill. Thanks!
 

Miraculix

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Thanks for the tips! I don't have a very good way to do a step mash, so was planning to do a single infusion mash targeting about 149F temp for 60 minutes.

When you say 5-15% fermentables, would that be by weight of the sugar relative to the grain bill weight? I assume so. Is the intent for adding the invert sugar to help the yeast with more simple fermentable sugars?

I am planning to start fermentation at 65-66F and gradually increase to about 68F. Do you recommend I keep it more at the 66F range for the entire fermentation? I have a fermentation chamber where I can control the temp.

Thanks again!
Sounds all good to me! Single step will also be fine. And the sugar, you already figured it out yourself :).
 
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troygarrett33

troygarrett33

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Just thought I would post an update after brewing a Deschutes Obsidian Stout clone, using the A09 Pub yeast. Only about a week in the keg, but it sure turned out nice :) . The numbers were: OG: 1.063, FG: 1.015, so it finished out pretty well with the A09. Thanks for your reassurances regarding the different look of the Pub yeast. It worked out great!

obsidian.jpg
 

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