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FunnyFungiName
Ninja Space Pirate


Registered: 01/15/18
Posts: 335
Last seen: 3 months, 5 days
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Can you overcook LME Agar?
#26411652 - 01/01/20 10:48 PM (4 years, 1 month ago) |
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While making some lme agar, I accidentally let my pc run an hour instead of my usual 20 minutes. Will the extra pc time mess up the consistency of the batch or is extra time not a big deal?
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narmaduke
Stranger


Registered: 08/23/17
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Last seen: 1 year, 1 month
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yeah you can caramelize the sugars, never happened to me so I am not sure how it would affect the quality.
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cronicr



Registered: 08/07/11
Posts: 61,436
Loc: Van Isle
Last seen: 2 years, 26 days
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Re: Can you overcook LME Agar? [Re: narmaduke]
#26411657 - 01/01/20 10:54 PM (4 years, 1 month ago) |
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Quote:
narmaduke said: yeah you can caramelize the sugars, never happened to me so I am not sure how it would affect the quality.
No not at our temps can you do this. Your fine op
--------------------
  It doesn't matter what i think of you...all that matters is clean spawn I'm tired do me a favor
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narmaduke
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Registered: 08/23/17
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Re: Can you overcook LME Agar? [Re: cronicr]
#26411664 - 01/01/20 11:03 PM (4 years, 1 month ago) |
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Quote:
bodhisatta said:
agar is sterilized in 20m at 15psi. I always usually go to 20m I would not go longer than 30-45m you risk caremelization of sugars in your media.
this is from bods agar tek and i thought i read the same thing other places.
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cronicr



Registered: 08/07/11
Posts: 61,436
Loc: Van Isle
Last seen: 2 years, 26 days
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Re: Can you overcook LME Agar? [Re: narmaduke]
#26411673 - 01/01/20 11:14 PM (4 years, 1 month ago) |
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250 isn't high enough to carmelize sugars
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  It doesn't matter what i think of you...all that matters is clean spawn I'm tired do me a favor
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narmaduke
Stranger


Registered: 08/23/17
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Last seen: 1 year, 1 month
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Re: Can you overcook LME Agar? [Re: cronicr]
#26411674 - 01/01/20 11:18 PM (4 years, 1 month ago) |
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Quote:
cronicr said: 250 isn't high enough to carmelize sugars
just looked and it says ~320F. good to know!
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FunnyFungiName
Ninja Space Pirate


Registered: 01/15/18
Posts: 335
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Re: Can you overcook LME Agar? [Re: narmaduke]
#26411691 - 01/01/20 11:34 PM (4 years, 1 month ago) |
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Badass! Half asleep on new years day I was planning to run this load 2 hours like grains until I realized what I was doing haha.
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SpunkyMonkey88
Stranger



Registered: 10/08/19
Posts: 1,331
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I worried the same shit but itll be fine. It does get darker the longer you cook it though which what freaked me out...
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,890
Loc: Milky way
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Sucrose breaks apart into glucose and fructose before caramelization temps. Especially with slightly acidic conditions. Malt agar is usually pH 5-6 (5.2-5.4 ideally if you're making beer) and malt naturally makes the pH in that area.
Fructose starts to caramelize at 230F but caramelization also is accelerated at pH less than 7.
Is it even a big deal? No I just wouldn't put agar in with grain jars
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curious.psychonaut
Stranger



Registered: 10/17/19
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Last seen: 4 years, 28 days
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Caramelization temps:
Quote:
Fructose 110°C (230°F) Galactose 160°C (320°F) Glucose 160°C (320°F) Sucrose 160°C (320°F) Maltose 180°C (360°F) Oligo/polysaccharides anywhere 110°C-180°C (230°F-360°F) depending on components
Sugar profile (mg/100g) of diff grains (from this recent paper):
Quote:

Sugar profile of a malt extract (100% barley) I found on the web (but not exactly brewer's LME):
Quote:
Fructose 1-2 % Glucose 7-10 % Sucrose 1-3 % Maltose 39-42% Maltotriose 10-15% Long Chain Sugars 25-30%
So, it depends on the grain/food component used. LME/Barley has a lot of Fructosans/Glucodifructose/Raffinose: oligo/polysaccharides which are mainly/mostly/partly fructose, accounting for 57% of sugars in the grain and apparently less (25-30%) in the extract. These would caramelize at 110°C (230°F).
BTW LME is not only sugars (though they're >90%): it also contains a significant amount of proteins (~5%), so Maillard's reaction also occurs which doesn't need high temperatures. However, at temps much below 150°C, it is probably too slow to matter (unless you heat your agar overnight or something).
-------------------- My LAGM2020 grow log
Edited by curious.psychonaut (01/02/20 05:46 AM)
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