Home | Community | Message Board


Mycohaus
Please support our sponsors.

Mushrooms, Mycology and Psychedelics >> Advanced Mycology

Welcome to the Shroomery Message Board! You are experiencing a small sample of what the site has to offer. Please login or register to post messages and view our exclusive members-only content. You'll gain access to additional forums, file attachments, board customizations, encrypted private messages, and much more!

Amazon Shop for: Agar, Malt Extract

Jump to first unread post. Pages: 1
Offlinekeepsdv8nu
Bodhidsatva
Registered: 02/28/05
Posts: 5
Last seen: 11 years, 9 months
Agar
    #3851741 - 03/01/05 01:51 PM (11 years, 9 months ago)

in what proportion would you add malt/agar/water to get a 1% Malt Extract Agar or 2% Malt Extract Agar etc.?
Thanx, Keepsdv8nu


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineAeolus1369
Dr. Seahorse
Male

Registered: 05/20/02
Posts: 367
Last seen: 7 years, 9 months
Re: Agar [Re: keepsdv8nu]
    #3852310 - 03/01/05 03:43 PM (11 years, 9 months ago)

% = percent = per hundred.

1g agar in 99g H20 = 1%
2g agar in 98g H20 = 2% etc

--Aeolus


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineBasidiocarp
Dr. BunsenHoneydew
Male User Gallery

Registered: 01/18/04
Posts: 395
Loc: Rogue's Island, USA
Last seen: 10 years, 4 months
Re: Agar [Re: Aeolus1369]
    #3855196 - 03/02/05 02:13 AM (11 years, 9 months ago)

Quote:

Aeolus1369 said:
% = percent = per hundred.

1g agar in 99g H20 = 1%
2g agar in 98g H20 = 2% etc

--Aeolus




I know this is totally anal and usually wouldn't make a huge difference for agar work, but as I recall percent solutions are defined as grams of solute per 100mL total final solution, not per 100mL of raw solvent. (This is because 1g of a solid rarely has an exact volume of 1mL.)

To be totally on point one would disslove the 1g agar in say 50mL water, and then bring the total volme of solution up to 100mL with additional hot water, to generate a true 1% solution.


--------------------
"...if the mind is actually part of a continuum, a labyrinth that is connected not only to every other mind that exists or has existed, but to every atom, organism, and region in the vastness of space and time itself, the fact that it is able to occasionally make forays into the labyrinth and have transpersonal experiences no longer seems so strange."

Visit the Psychonautical Society


Post Extras: Print Post  Remind Me! Notify Moderator
Offlinechocbruce
Learned Student

Registered: 11/30/04
Posts: 231
Loc: ...
Last seen: 6 years, 7 months
Re: Agar [Re: keepsdv8nu]
    #3855307 - 03/02/05 02:35 AM (11 years, 9 months ago)

If you don't have access to lab equipment, I'd suggest trying 2 cups water to a teaspoon of water. that will give you approximately a 1.03% solution BY VOLUME. If you wish to get ~2.06% BY VOLUME, use 2 teaspoons, or half the amount of water for a smaller batch.

1 teaspoon = 1/48 cup

This is innacurate because it is by volume, tho. If you know something's volume, you can't know its density without knowing its mass; this is why people here only use weight, which makes up for variation, although, in the case of agar, to an extent I feel that is it forgiving; a difference of 1% probably won't change a thing.


--------------------
I look for answers and present ideas, but in no way shape or form endorse, or partake in, growing, or manufacture of substances, or plants, or any specie that is illegal in your neck of the woods. I do however, tear the tags off of my mattresses. Be warned.


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineAnnoA
Experimenter
 User Gallery

Folding@home Statistics
Registered: 06/18/99
Posts: 24,121
Loc: my room
Last seen: 2 months, 15 days
Re: Agar [Re: chocbruce]
    #3855561 - 03/02/05 03:52 AM (11 years, 9 months ago)

>a difference of 1% probably won't change a thing.

Not only probably, but definitely.


Post Extras: Print Post  Remind Me! Notify Moderator
InvisiblePinback
Stranger
 User Gallery

Registered: 07/20/02
Posts: 784
Loc: Northern Europe
Re: Agar [Re: Basidiocarp]
    #3856188 - 03/02/05 09:56 AM (11 years, 9 months ago)

Actually he was correct. Percent is unitless, which implies that the part and the whole is of the same unit. It is also, by convention, always in mass/mass unless stated otherwise.

Perhaps you are thinking of molarity, which is defined as moles of solute per liter of solution.


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineBasidiocarp
Dr. BunsenHoneydew
Male User Gallery

Registered: 01/18/04
Posts: 395
Loc: Rogue's Island, USA
Last seen: 10 years, 4 months
Re: Agar [Re: Pinback]
    #3860162 - 03/03/05 12:04 AM (11 years, 9 months ago)

Quote:

Pinback said:
Percent is unitless, which implies that the part and the whole is of the same unit. It is also, by convention, always in mass/mass unless stated otherwise.




Is it really? Perhaps I'm taking the chemist's view on things where it's usually assumed to be mass/volume, as I think I recall from orgo. I mean, when we made up a 50% NaOH solution we weighed 50g NaOH, dissolved in H2O and brought up to a final volume of 100mL. Am I totally having a brain fart on this or what?

But I do agree with Anno, as far as this agar case is concerned we're just splitting hairs, it doesn't matter. But I do want to know if it's usually assumed mass/mass or mass/volume or what, just for tee hees.


--------------------
"...if the mind is actually part of a continuum, a labyrinth that is connected not only to every other mind that exists or has existed, but to every atom, organism, and region in the vastness of space and time itself, the fact that it is able to occasionally make forays into the labyrinth and have transpersonal experiences no longer seems so strange."

Visit the Psychonautical Society


Post Extras: Print Post  Remind Me! Notify Moderator
Offlinedumbsnake34
Crazy Dude
Registered: 12/14/04
Posts: 88
Last seen: 2 years, 1 month
Re: Agar [Re: Basidiocarp]
    #3860507 - 03/03/05 01:28 AM (11 years, 9 months ago)

I am a chemist in training right now. A dimensionless quantity must be the same units over units because they must cancel. This is basic highschool chemistry and it doesn't change in grad school (or anywhere in the middle). You are probably just confused because at standard conditions (approximately room conditions) 1g of water is 1mL exactly.

As for the original question. Being off by 10% of the 1% is very tolerable while being off by even half a percent is very intolerable.


--------------------
mmmm, daydreaming


Post Extras: Print Post  Remind Me! Notify Moderator
InvisibleATWAR
Connoisseur

Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
Re: Agar [Re: dumbsnake34]
    #3860612 - 03/03/05 02:00 AM (11 years, 9 months ago)

Quote:

dumbsnake34 said:
As for the original question. Being off by 10% of the 1% is very tolerable while being off by even half a percent is very intolerable.





I am not sure if I understand this correctly but basically you are saying that a 0.1% mistake is tolerable, but 0.5% is not... Correct?

If so I disagree. I have more than doubled the concentration of both agar and malt in separate experiments (4% agar, and 4.5% malt), and results were slightly hindered growth in high sugar concentrations. Agar did not seem to have any negative effect. While it was not the perfect medium, it did work as intended. If you were in a situation where you could not exactly weigh out ingredients then measuring by volume will be approximate enough.

I have grown mycelium on malt concentrations ranging from 0.5% - 4.5% and agar concentrations from 1.0% - 5.0%. When in doubt it would be best to go heavy on agar, and light on sugar... -JMHO




Too much malt did cause the growth to slow, but it was still healthy:


--------------------
To give is to live...



Post Extras: Print Post  Remind Me! Notify Moderator
OfflineBasidiocarp
Dr. BunsenHoneydew
Male User Gallery

Registered: 01/18/04
Posts: 395
Loc: Rogue's Island, USA
Last seen: 10 years, 4 months
Re: Agar [Re: dumbsnake34]
    #3860701 - 03/03/05 02:21 AM (11 years, 9 months ago)

Quote:

dumbsnake34 said:
I am a chemist in training right now. A dimensionless quantity must be the same units over units because they must cancel. This is basic highschool chemistry and it doesn't change in grad school (or anywhere in the middle)..




No kidding it's high school chemistry snappypants. You can define percent solutions as W/W or W/V. Weight over volume is actually the most common method used, which is what I was talkng about and is what we used in the lab I worked in.

You might want to continue your chemistry training by reviewing percent solutions here . Directly from this site is an example:

1. What is the percent concentration of a solution that you made by taking 5.85 g of NaCl and diluting to 100 mL with H20?

5.85 g/100 mL = 5.85% W/V solution of NaCl

Note that one dilutes to a final volume of 100 when doing W/V. You don't dump 5.85g into 100mL H2O, or into 94.15mL H2O.


--------------------
"...if the mind is actually part of a continuum, a labyrinth that is connected not only to every other mind that exists or has existed, but to every atom, organism, and region in the vastness of space and time itself, the fact that it is able to occasionally make forays into the labyrinth and have transpersonal experiences no longer seems so strange."

Visit the Psychonautical Society


Edited by Basidiocarp (03/03/05 01:22 PM)


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineAeolus1369
Dr. Seahorse
Male

Registered: 05/20/02
Posts: 367
Last seen: 7 years, 9 months
Re: Agar [Re: Basidiocarp]
    #3875946 - 03/06/05 04:42 AM (11 years, 9 months ago)

Wow, I had no idea I would inadvertently set off such a flurry of debate. In my defense though (whether I'm right or wrong), allow me to prove that it makes a negligible difference.

The most volume 1 gram of agar could theoretically occupy in solution is 1 ml and the least (again theoretically) is 0 ml. This means for a 1% solution, you would add 99 and 100 ml water respectively. So at the very very most, you're off by 1 ml water in either direction which is barely 1% error margin (i.e. you get a 1.01% solution or god forbid, a 0.99%). Since this is far less than the inherent weighing errors outside of an actual laboratory, I think we're all fine regardless of your definition of "1% solution."

--Aeolus


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineBasidiocarp
Dr. BunsenHoneydew
Male User Gallery

Registered: 01/18/04
Posts: 395
Loc: Rogue's Island, USA
Last seen: 10 years, 4 months
Re: Agar [Re: Aeolus1369]
    #3878901 - 03/06/05 07:58 PM (11 years, 9 months ago)

I don't think you need to defend yourself. I've already agreed with Anno ^^^^above^^^^ that in this particular agar case the difference is negligible, and the outcome would not be affected.

I simply wanted to show that W/V make-up of per cent solutions is in fact a common and widely accepted methodology that insures consistency in scientific protocol.


--------------------
"...if the mind is actually part of a continuum, a labyrinth that is connected not only to every other mind that exists or has existed, but to every atom, organism, and region in the vastness of space and time itself, the fact that it is able to occasionally make forays into the labyrinth and have transpersonal experiences no longer seems so strange."

Visit the Psychonautical Society


Edited by Basidiocarp (03/07/05 12:08 AM)


Post Extras: Print Post  Remind Me! Notify Moderator
InvisiblePinback
Stranger
 User Gallery

Registered: 07/20/02
Posts: 784
Loc: Northern Europe
Re: Agar [Re: Basidiocarp]
    #3882548 - 03/07/05 02:56 PM (11 years, 9 months ago)

I think that this thread shows that to ensure concistency, one should also make a note of what the percent sign refers to.  :wink:


Post Extras: Print Post  Remind Me! Notify Moderator
Jump to top. Pages: 1

Amazon Shop for: Agar, Malt Extract

Mushrooms, Mycology and Psychedelics >> Advanced Mycology

Similar ThreadsPosterViewsRepliesLast post
* Agar times xburn 903 5 05/11/05 05:29 PM
by X24
* High Volume One Pot Liquid Tek? optigram 1,252 12 11/27/03 10:22 AM
by micro
* agar uses... dbt123 1,032 11 05/05/09 12:14 PM
by fastfred
* WTF Agar?
( 1 2 all )
Morelman 4,058 31 03/14/07 06:31 PM
by fastfred
* re: "average" agar cultivation temperature? ucsdmolpath 2,447 16 12/28/14 03:29 AM
by krypto2000
* Some proven agar nutrient media recipes Una 4,917 11 10/03/04 03:15 PM
by YSr
* gar.. dog food agar questions ( silly obstruction..) vampirism 1,334 5 08/10/03 02:58 PM
by micro
* Salicylic Acid Agar
( 1 2 all )
P.Menace 4,169 38 08/10/08 06:16 PM
by P.Menace

Extra information
You cannot start new topics / You cannot reply to topics
HTML is disabled / BBCode is enabled
Moderator: Prisoner#1, RogerRabbit, EvilMushroom666
1,520 topic views. 1 members, 9 guests and 1 web crawlers are browsing this forum.
[ Toggle Favorite | Print Topic | Stats ]
Search this thread:
Myco Supply
Please support our sponsors.

Copyright 1997-2016 Mind Media. Some rights reserved.

Generated in 0.055 seconds spending 0.004 seconds on 14 queries.