Can you re-melt agar-agar?

[Togath]

So... I tried experimenting with agar jellies again, and ended up with a translucent hard dry brick, somehow.
The only english on the package said "add 120gm boiling water", so I added a cup(which google said was that amount)... and yeah, I suspect I actually need more water.

So, do I need to buy more agar? Or can I melt my brick down? I used, according to the package, 25 grams of agar-agar powder(which... seems small? Is it supposed to make a brick?).

[brian 333]

Time is also an issue. Cook longer, more set, if I recall. Pectin is like that too.

You might be able to thin it with water, but I've never tried.

[Eldan]

You can absolutely re-melt it. Put it in a bowl, pop it in the microwave for like five minutes on the highest setting.

Though... how much for 120ml water? Can't be much more than a tiny sliver, surely?

I haven't ever used cooking agar, but for laboratory agar, we use around 0.5-1% by weight, so 5 to 10 grams on a liter of water. That's uh... something in Imperial units. 25 grams should be enough for like half gallon of water or more, assuming it's weaker than laboratory agar.

[Fri]

Yeah, you might've misunderstand the instruction somehow. The usual packet of agar powder here, which is 10g packet, is supposed to be dissolved in a litre of water (and a cup of sugar) to get a bowl of agar dessert.

[Brother Oni]

I haven't ever used cooking agar, but for laboratory agar, we use around 0.5-1% by weight, so 5 to 10 grams on a liter of water. That's uh... something in Imperial units. 25 grams should be enough for like half gallon of water or more, assuming it's weaker than laboratory agar.

The issue is that the Americans have 2 'cup' measurements, the legal cup and the customary cup.

1 legal cup = 240 mL
1 customary cup = 237 mL

Looking at a generic food agar recipe, agar is 3% by weight for a firm jelly, down to 1% for a more liquid one. Assuming 25g of powder, that's 833 - 2500 ml (3.5 to 10.5 customary cups).

Togath's concoction is ((25/237)*100) = 10.5% w/w, so a little over 3 times too concentrated, so I'm not surprised she ended up with a brick this time. :smalltongue:

From what I remember of her last attempt, it's an improvement, so keep on at it, Togath! :smallbiggrin:

[halfeye]

The issue is that the Americans have 2 'cup' measurements, the legal cup and the customary cup.

1 legal cup = 240 mL
1 customary cup = 237 mL

That may well be true, but the rest of us have cups and mugs that are sizes that seem to be entirely down to how the manufacturer of the cup or mug was feeling on the day that the mold was made (and mugs and cups made by actual potters are going to vary a lot more than that). My main mug is about 500 ml/cc, but it's probably something like 490cc if you measure it carefully (which I obviously haven't).

[Fri]

There might be a slight misunderstanding here. The "cup" in US cooking recipe isn't just random cup, it's actually a specific measurement, like how when you say something is three feet tall it's not just any random feet. But yes, it's still feel as arbitrary and weird as using feet as measurement :smalltongue:

[Brother Oni]

There might be a slight misunderstanding here. The "cup" in US cooking recipe isn't just random cup, it's actually a specific measurement, like how when you say something is three feet tall it's not just any random feet. But yes, it's still feel as arbitrary and weird as using feet as measurement :smalltongue:

Another example is 'spoons' with tea spoon (5ml), dessert spoon (10ml) and table spoon (15-20ml depending on country), having an actual volume they represent.

This is blurred a lot as you can have level, rounded or heaped spoon variant measurements for dry/solid ingredients, plus varying compression instructions (1 cup brown sugar versus 1 cup brown sugar firmly packed can potentially be up to a 20% difference in weight).

To be honest, I'm not surprised when most professional cooks just eyeball it and taste test throughout the cooking process, adjusting as needed.

[tyckspoon]

To be honest, I'm not surprised when most professional cooks just eyeball it and taste test throughout the cooking process, adjusting as needed.

Or just say screw it and do everything by weight, because it's the most objective way to give an amount of something; 500g of something is 500g regardless of how you heap it or pack it down.

[Eldan]

Over here, pretty much all recipes are in grams and dl, with the occasional spoon. That's why American recipes are so infuriating to copy.

[Togath]

Update; my third try at agar jelly worked! It was a bit watery(since I tried sticks this time instead of powder, and used a little too much liquid), but still tasty!.. Meanwhile I ruined my fourth attempt by using lime juice which prevented it setting.:smallredface:

[Brother Oni]

Update; my third try at agar jelly worked! It was a bit watery(since I tried sticks this time instead of powder, and used a little too much liquid), but still tasty!.. Meanwhile I ruined my fourth attempt by using lime juice which prevented it setting.:smallredface:

Congratulations. :smallbiggrin:

Yeah, most instructions don't recommend acidic liquids as it degrades the agar, preventing it from setting as you've discovered.

[Fri]

I just searched about it, since I remember that pineapple mess with gelatin but not with agar, that's why it's often recommended to replace gelatin with agar in recipes with pineapple.

Apparently lime can mess with agar, you're supposed to use twice the amount of agar in recipes with limes.

https://wholefoodcooking.com.au/2011/09/the-many-roles-of-agar/

[Togath]

Finally making progress... seems about one teaspoon of agar firmly(but, like, not brick-firmly) sets about a cup of water. I still feel like I could make this a smoother texture, but I am getting closer, I think.

[Brother Oni]

Finally making progress... seems about one teaspoon of agar firmly(but, like, not brick-firmly) sets about a cup of water. I still feel like I could make this a smoother texture, but I am getting closer, I think.

Which is (5ml/240ml x 100) = 2.1%, making it on the slightly firmer end of the scale. I'm unfamiliar with working with agar, but you could try half or three quarters of a teaspoon with a cup of water and more thorough mixing to better homogenise the mixture before setting.

[Fri]

May I ask how do you make your agar? Because I never had any problem making one before, so I'm curious on your work process. I wonder if it's different type of agar or somethign like that

Here's how I usually do it:

1. Mix 1 pack of agar powder (which is 10g) on a litre of water (4 cups I guess?)
2. Put a cup of sugar and whatever flavour you want.
3. Bring them all to a boil and mix them well.
4. Put them to a big bowl, and left them overnight to set.

My mom likes to put biscuits at the bottom of the bowl at step 4, so the agar has a layer of it when set. You can also put fruits at step 4.

[Cocorito]

I recentky tried preparing an agar jelly but the recipe advised to freeze the jelly and I ended up with a block of ice more or less.
Would re-melting it require adding more agar agar or should I just keep the one added initially (quantities were according to what advised in the packaging)?