Ask The Brewmasters

Hello everyone.
Do any of you prefer to use agar prepared with wort made at the plant to prepare the yeast slants, instead of using the classic agars like YM or YPD?

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Magaly Rodriguez-Saavedra
Mahou-San Miguel
Lleida
+34658202462
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This message was posted by a user wishing to remain anonymous

Magaly,

While it's certainly possible to use wort prepared at the brewhouse, we use DME (dried malt extract) and agar powder to allow for more control and freedom from our brew schedule as we often brew exotic styles (high gravity, sours, dark beers, etc). Here's our recipe for slants:

(per 100 mL distilled H₂O)

• 0.6 g DME
• 1.1 g dextrose
• 0.3 g yeast extract
• 2.2 g agar powder

This is very similar to YM agar, but can be prepared in the lab with readily available ingredients to most brewers and is cost preferable over buying premixed agar powders. If you don't have access to these reagents, I'd supplant all the dry ingredients with 100 mL of wort and combine with 2.2g of agar. Hope that helps!

Cheers,
AP

Thank you for your suggestion. I will give it a try, I hope to increase the biomass compared to what I already get using YM agar.

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Magaly Rodriguez-Saavedra
Mahou-San Miguel
Lleida
+34658202462
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Original Message:
Sent: 01-27-2023 10:19
From: Anonymous Member
Subject: Agar for yeast slants propagation

This message was posted by a user wishing to remain anonymous

Magaly,

While it's certainly possible to use wort prepared at the brewhouse, we use DME (dried malt extract) and agar powder to allow for more control and freedom from our brew schedule as we often brew exotic styles (high gravity, sours, dark beers, etc). Here's our recipe for slants:

(per 100 mL distilled H₂O)

• 0.6 g DME
• 1.1 g dextrose
• 0.3 g yeast extract
• 2.2 g agar powder

This is very similar to YM agar, but can be prepared in the lab with readily available ingredients to most brewers and is cost preferable over buying premixed agar powders. If you don't have access to these reagents, I'd supplant all the dry ingredients with 100 mL of wort and combine with 2.2g of agar. Hope that helps!

Cheers,
AP

Hi Magaly,

Using wort with agar is a great way to make slants. This will provide a perfect growth medium and help condition the yeast, unlike YM and YPD. 

We provide premade sterile wort agar plates for breweries that are unable to prepare their own:

https://brewingscience.com/product/wort-brewing-yeast-40-shipping-30-sterile-pre-poured-plates/

Please reach out if you have any more questions on slants/media.


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Jason Lima
Brewing Science Institute
Woodland Park CO
719-482-4895
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