Gelatin Conversion

[gfron1]

I don't know if this will become our catch-all leaf gelatin topic, but here's another question.

A couple of weeks ago I accidentally soaked 12 sheets instead of two. Since they were in ice water I just put the remaining 10 sheets in the walk-in in the water that I originally soaked them in. Two weeks later I found them and they feel as if they are still perfectly usable.

They weren't covered so I won't use them as they may have absorbed flavors, but am I wrong in thinking these are usable? And if so, why would I not just keep a batch in the walk-in all the time for use as I need them?

[gap]

Good question. I seem to remember that gelatin will keep absorbing water past the optimal point. I've been told that the soaked gelatin should be ablout 6-7 times the weight of the unsoaked gelatin. Maybe if you leave it too long it absorbs too much water??? I'm just guessing though.

[McDuff]

It's mostly protein and will get moldy after a while. I had that happen with powdered gelatin. Learned to mix it 1 part to 5 parts water, and then use one oz of that for every pound needed to be gelled. so I mixed up a bunch, and it turned moldy fairly quickly.

I don't know if this will become our catch-all leaf gelatin topic, but here's another question.

A couple of weeks ago I accidentally soaked 12 sheets instead of two.  Since they were in ice water I just put the remaining 10 sheets in the walk-in in the water that I originally soaked them in.  Two weeks later I found them and they feel as if they are still perfectly usable. 

They weren't covered so I won't use them as they may have absorbed flavors, but am I wrong in thinking these are usable?  And if so, why would I not just keep a batch in the walk-in all the time for use as I need them?

←

[Adam Balic]

Hi,

I'm quoting directly from Martin Lersh's book on hydrocolloids (http://khymos.org/recipe-collection.php)

The most likely problem is that there are different strengths of gelatine depending on the type of sheet used.

The bloom strength is the gelling strength and it works as follows. The stronger the bloom strength, the lighter the sheet (to give approximately equivalent gelling strengths)

Name  (Bloom Strength)  [grams/sheet]

Bronze (125-155) [3.3]

Silver (160) [2.5]

Gold (190-220) [2.0]

Platimum (235-265) [1.7]

So if the recipe called for 10g of gelatin, it may have been 10g of bronze and if you used platinum, it would have been around twice as set.

Typically for Panna cotta, you'd use around 1% gelatin.  For 500 ml of cream plus sugar, vanilla, etc you'd use around 5.6g or just over three sheets. For Bronze gelatin, this would be 3.3g x 3 ~ 10g, so that is the likely problem.

With different strengths of gelatin, it is somewhat complicated, hope this helps.

←

Any information on the bloom strength/weight of titanium gelatin sheets? Annoyingly it is the most common variety sold locally.

[nickrey]

Any information on the bloom strength/weight of titanium gelatin sheets? Annoyingly it is the most common variety sold locally.

←

The best I can find is that 5g of titanium gelatin will set 250ml of water to a firm set.

This equates to the numbers given above as 2.5g of silver will do the same thing.

Once can reason that the bloom strength of titanium is less than the others but I couldn't find it quoted anywhere. The one formula I found for converting between weights for different bloom strengths was wrong and using linear regression did not give a perfect fit.

[Adam Balic]

Any information on the bloom strength/weight of titanium gelatin sheets? Annoyingly it is the most common variety sold locally.

←

The best I can find is that 5g of titanium gelatin will set 250ml of water to a firm set.

This equates to the numbers given above as 2.5g of silver will do the same thing.

Once can reason that the bloom strength of titanium is less than the others but I couldn't find it quoted anywhere. The one formula I found for converting between weights for different bloom strengths was wrong and using linear regression did not give a perfect fit.

←

Thanks for that, confirms what I found empirically. So for making a non-turned out pannacotta would you go for 1% or 2% w/v gelatin/liquid.

Edited March 12, 2009 by Adam Balic (log)

[nickrey]

Any information on the bloom strength/weight of titanium gelatin sheets? Annoyingly it is the most common variety sold locally.

←

The best I can find is that 5g of titanium gelatin will set 250ml of water to a firm set.

This equates to the numbers given above as 2.5g of silver will do the same thing.

Once can reason that the bloom strength of titanium is less than the others but I couldn't find it quoted anywhere. The one formula I found for converting between weights for different bloom strengths was wrong and using linear regression did not give a perfect fit.

←

Thanks for that, confirms what I found empirically. So for making a non-turned out pannacotta would you go for 1% or 2% w/v gelatin/liquid.

←

My wife likes them mousse like rather than jelly like so I'd go for the least possible to set, particularly if it was non-turned out.

[CtznCane]

I was fixing a recipe from Robuchon that galled for a gelatin leaf. The weight listed for it was 6 grams. Are gelatin leaves more of a European thing? I know weight wise, 1 packet of Knox gelatin is 7 grams. Not a significant difference I wouldn't think to the recipe. Certainly where I live now in kentucky leaves will be hard to find, but even living in the SF bay area I never noticed them in any of the stores (though I wasn't keeping a lookout for them either.)

Since the leaf was to be soaked and then taken out, if one is using powdered, what volume of water do you use? I wound up using just enough water to have the gelatin disolve leaving somewhat of a moist sheet. Is there an easy formula for doing this?

Is there an advantage to gelatin sheets over powder product wise? From a convenience standpoint it seems the leaves could have an advantage at times. Also if anyone knows where one would find them, and under what listing, to buy online.

[OliverB]

I'd love to know too, I'm in the SF Bay and have been looking for them in every supermarket I go to, no luck. The powder is everywhere, but lists nothing like "one pack = one sheet" or any such instructions. Are the leaves/sheets just an old fashioned way of packing? An European way?

For online source, just type it into Amazon, they list several. Amazon has everything it seems.

As I can find the powder in any store here, I'd prefer to know the difference/similarities though, instead of having to pay for shipping on a pack of gelatin.

Oliver

[OliverB]

Oh, just found this (google is your friend):

One package (1 tablespoon) of powdered gelatin equals 4 sheets.

from here:

http://www.recipezaar.com/library/getentry.zsp?id=431

and google for gelatin sheet to see more buying options. I forgot about it, but as mentioned on some site, we used them as window glass on gingerbread houses when I was little.

Seems you can use either, pros seem to believe that sheets make clearer gelatin, probably not important for home use or at least for a first try of a recipe.

Let us know how your recipe is turning out! I have that book on my "next to get" list :-)

[Tri2Cook]

From the Baking & Pastry Index, a whole thread on: Gelatin Conversion.

Edited May 31, 2009 by Tri2Cook (log)

[Renn]

I see sheet gelatin at retail very infrequently, even here in SF. However, The Pasta Shop in Berkeley does carry Bronze Sheets most of the time. There may be others that carry sheets, particularly specialty bakery supply shops, but your best bet for silver or other "more potent" sheets would be online.

[gfron1]

Suck it up and buy a box from ChefRubber and you'll never go back. I find leaf so much more gentle once you get used to using it. And just go for the silver leaf as it seems most common in the cookbooks.

btw, for your recipe, if it calls for 6 g of gelatin, they are referring to 6 g of dry leaf - depending on who you ask, 2 or 3 sheets. Don't worry about the water, just fill a bowl with water, add ice cubes (or a bag of peas in my kitchen), and add the gelatin. In about 10 minutes they'll be soft and usable. The ice softens the gelatin without melting it.

Edited May 31, 2009 by gfron1 (log)

[cookin4acravin]

I was trying to convert gelatin sheets to an amount of Knox gelatin grams or teaspoons. In Johnny Iuzinni's book "Desserts Fourplay" he says that all gelatin sheets are equal by weight but this contradicts what Claire Clark says in Indulge where shes says they are equal by sheets but not by weight.

If I understand bloom correctly (which I probably don't), her statement is more true than Iuzinni's. I did some math of how I thought bloom worked.

If 2.5 grams x 160 bloom (silver sheet) = 400 and 2 grams x 200 bloom (gold sheet) = 400 meaning that they are the same strength if calculated by sheets. I read that Knox powdered gelatin is 225 bloom so I took 400 (the bloom for a sheet according to my theory) and divided it by 225 and got 1.77 meaning 1.7 grams of powdered should equal one sheet. I then took this and divided it by 2.33 which i found to be the amount of grams of gelatin powder in a teaspon and got .76 which means that 3/4 a teaspoon of powder is equal to a sheet and 1.5 teaspoons is equal to 2 sheets which I found many places throughout the internet. Is my calculation right or do I need to use some other conversion factor to get amount of sheets of gelatin. I've seen many different but I don't want to use too much gelatin and make my mousse rubbery.

[RobertM]

I wondered the exact same thing a while ago, but, I took the easy way out I'm afraid. I called Knox and asked them how much Knox would equal one sheet of gelatin. The person I spoke to looked it up in their data base and I was informed that one of their packets of gelatin is equal to one sheet of gelatin. I don't have the weight amount of a packet directly in front of me and my kitchen is about 15 miles away from me right now - (I want to say it's one ounce, but, I am siting that from memory) but, that is the explanation I got directly from Knox - and it's worked for me in every formula I've used with that conversion -

[John DePaula]

Silver strength or Gold? The folks at Knox haven't given you complete information.

You will find the following topics helpful:

Help! Leaf gelatin question...

and

Gelatin Conversion

I don't do a lot with gelatin but I seem to recall that HeatherM had it pretty well figured out: HeatherM's post on gelatin conversion

Edited December 4, 2009 by John DePaula (log)

[cookin4acravin]

I am trying to convert from silver strength to powdered Knoxx. I read somewhere that each packet is not always the same weight so I'm not so sure about using that conversion. I looked at the forumns but was so confused with all the contradicting views.

[John DePaula]

I am trying to convert from silver strength to powdered Knoxx. I read somewhere that each packet is not always the same weight so I'm not so sure about using that conversion. I looked at the forumns but was so confused with all the contradicting views.

From HeatherM's post:

3 Silver sheets = 2.5g x 3 = 7.5g

Silver to Knox conversion is:

Silver (g) x 0.84 = Knox (g)

7.5 x 0.84 = Knox (g)

6.3 g = Knox

Therefore, 1 Silver sheet = 6.3 g / 3 = 2.1g Knox.

1 Silver sheet = 2.1g Knox powder

[cookin4acravin]

Thanks I will try that but is there a specific amount on how much water you add for powdered gelatin? A rough guideline or formula?

[Lee Gomes]

A Pierre Herme vanilla tart recipe calls for seven gold gelatin leaves. How many teaspoons of Knox is that? (I've searched the eGullet threads on this topic, but found the formulas therein to be bloomin' impossible to follow.)

FWIW, this is the recipe.

http://kitchenmusings.com/2009/07/pierre-hermes-vanilla-tart.html

[John DePaula]

Well, I'll take a stab at it...

From HeatherM's post (here) we see the following formula:

Knox x 1.06 = Gold

Therefore:

Gold / 1.06 = Knox

So plugging in our real world numbers and assuming that 1 Gold Sheet weighs 2g:

2g x 7 sheets = 14g Gold

14g / 1.06 = 13.2g Knox

So if an envelope of Knox is 6g, you'd need about 2-1/5 envelopes of Knox for 7 Gold Sheets.

David Lebovitz has a great article explaining all of this more succinctly on his blog: David Lebovitz: How to Use Gelatin

[QbanCrackr]

what would the conversion be in the case of mousses? 100g puree:100g cream:1 sheet gelatin (i'm assuming its gold)

or should i just buy a box of silver and play with it until i find what works

-d

[mkayahara]

There's a great thread on gelatin conversion here. Hope that helps!

[nickrey]

There are lots of threads on this already.

This post has information on equivalencies that should assist you.

[formula400]

right please bear with me, my maths suck, at work anmd everywhere i have worked we have always used bronze leaves, but a while ago we get a box of gold in, did`t know how to use it.

right if i make something that needs 100g of bronze how much silver or gold would it take???

sorry for asking.

cheers