paulraphael

Sounds like way too much!

If this is for health reasons you're shooting yourself in the foot. Dextrose is only 70-75% as sweet as sucrose, so to get the equivalent flavor, you'll have to use 33 to 42% more of it. Dextrose is sugar. It's no less sugar than sucrose. Dextrose is indeed more hygroscopic than sucrose. For this reason a lot of pastry chefs add some, either dry or in syrup form to cakes and ganaches and confections. It's to keep things moist and to retard crystalization. But it's usually around 10%, never 100%. Glucose also tastes different from sucrose. I don't know anyone who prefers it. The taste is fine in small proportions but not large.

That's probably to hydrate / activate one of the gums. Annoying when a rep can't do more than read the instructions to you.

Pastrygirl, if it comes out the way you like then you're doing it right! I don't know Cremodan specifically. It could only substitute entirely for eggs if it includes emulsifiers. Getting rid of eggs means you need extra stabilization and also emulsification. If you're using stabilizers along with egg custard, you'll just end up needing less stabilizer to get the texture right.

A single one or two gallon batch ins't too tedious, but someone makeing a few flavors a day in those quantities will be stirring a lot of bowls floating in ice baths. This may be what pastry interns are for.

Recipes scale easily enough. The challenge is hardening big batches quickly enough to keep the ice crystals small. Ice cream stores use a hardening cabinet ... basically a -40° flash freezer. There are smaller versions for restaurants. The other issue is cooling custard-based recipes quickly enough to avoid health hazards. For big batches you have to use an ice water bath before aging the mix, which will get tedious.

The Migoya recipe I have specifies 0.35% stabilizers, made of 1 part xanthan, 1.75 parts lucust bean gum, 1.75 parts guar gum. This might work in lower quantities than your gums, since all three of these ingredients are synergetic (superadditive). But it might not! I don't have enough experience with carrageenan to offer any real guidance. My references say it forms a "firm, brittle gel," while guar, lcb, and xanthan are merely "thickeners." It's possible that carageenan just has a more radical effect and needs to be used in smaller quanities to keep the textures from getting exaggerated. This is just a guess. I think your inclination is probably right, to reduce the total stabilizers, or at least reduce the carrageenan.

That's a great point. I've noticed this when I'm not buying fancy cream from artisinal dairy. It's frustrating, because the cartons are vague about how much is in there. I've never tried figuring it out or compensating for it, but it probably makes at least a small difference. The carrageenan is used as a whipping aid.

Is there carrageenan in it? That will work much more powerfully if there's calcium around. Gums in general are really powerful, especially in certain combinations. It can be a challenge mixing in small enough quantities for home-sized batches.

For sorbets I use gelatin (0.15%) and xanthan (0.05%). Same ingredients but different proportions than for ice cream. People like pectin because it allows them say the sorbet is vegetarian, but I don't think it's as good a stabilizer as gelatin. If veggie is important, I'd go for the gums. They're more effective than starches and give better texture than pectin. Pectin exists on its own in many fruits. The quantity of stabilizer you use should probably be modified with this in mind. Here's some info I've compiled: High pectin content fruits: Citrus skins (oranges, tangerines, grapefruit, lemons, limes, etc. - the pectin is high in the skin but low in the fruit), tart cooking apples, crab apples, most plums, lemons, and wild grapes (Eastern Concord variety), cranberries and boysenberries. Blackberries. Medium pectin fruits: Apricots, rhubarb, quince Low pectin fruits: Cherries, grapefruit, grape juice, grapes (other than wild and Concord types), melons, oranges Very Low pectin fruits: Nectarines, strawberries, peaches, pears, figs, elderberries, raspberries, grapes (Western Concord variety), guava, pomegranates.

I don't have Francisco Migoya's Frozen Desserts book ... i read that it has a recipe for sorbet stabilizer made from some combination of carboxymethylcellulose, guar gum and locust bean gum.

Aging ice cream isn't about flavor; it's about allowing the fats to fully crystalize, and the proteins and polysaccharides to fully hydrate. This all improves body, texture, and whipability. Having the mix chilled as much as possible also speeds freezing, which gives you the smallest ice crystals. I don't know about cornstarch pudding mixes. Is this being used in an ice cream recipe? I experimented briefly with corn starch as an ice cream stabilizer and did not find it as good as gelatin or gums. Starches in general perform pretty poorly. Especially arrowroot. That's the biggest failed experiment I've had.

Cool, let us know.

Do you (or someone else) happen to have a directional guideline for the ratios of different ingredients? I have all of them separately so I would like to make my own mix. This is a big topic, because many of the ingedients are superaditive (meaning that 1+1 = more than 2). So it’s not just that each ingredient has a unique effect, but that many combinations have unique effects as well. I haven’t found a good primer on constructing combinations. My own formula took a lot of work, and it just includes two ingredients that exhibit no superaditivity. The Corvitto book offers only the most general overview. Evan at cookingissues.com sent me the following recipe: 
100g Xanthan Gum
175g CP Kelco Unflavored Locust Bean Gum
175g TIC Gums Pretested Flavorless Guar Gum
50g Mono-glycerides
50g Di-glycerides
[Mix all ingredients together, then sift and store in an airtight container.] This mix is intended to make up 0.35% of the recipe by weight. The glycerides are emulsifiers, not stabilizers. He sent me this during a conversation about eliminating eggs from ice cream. If your recipe has eggs, you could omit the glycerides and probably use a lower percentage of this mix. He recommends a minimum stablizer content of 0.3%, and a maximum of 1%. Unfortunately, this is nothing more than a recipe. There’s no theory or background included, so you’d be on your own to experiment. But it’s a starting point. This information originated with Chef Francisco Migoya, who used to be Thomas Keller’s executive pastry chef. I don’t know his ice cream first hand (sadly!)

I'm a big fan of the combination of gelatin and xanthan gum. These don't have the potency of the superaditive combinations used in commercial ice cream, so you have to use more. But this is a good thing if you're making small batches. You can measure these ingredients in 10ths of a gram instead of 100ths. I find gelatin to be unsurpassed in mouth feel and melting qualities. Its thickening power is dependant on temperature, so it has comparatively little effect on the viscosity of the ice cream after melting in your mouth. Xanthan is a stronger stabilizer in ice cream, and is unaffected by temperature. It thickens the mix even after melting. You have to be careful to not overdo the xanthan. Just like when thickening sauces, you can get unpleasant textures if the concentration is too high. I usually use about 1g/L gelatin and 0.3 to 0.4g/L xanthan. Most pastry chefs I know buy pre-mixed ice cream stabilizers. These usually include a combination of guar, locust bean gum, and some variety of carageenan. The mixtures can be pretty high tech and are effective in minute quantities. If you don't want to go crazy experimenting, these are a perfect solution. I shy away from them because I don't want to be dependent on any manufacturer for a proprietary formula. If they change or discontinue it, then I have to start over. This was my torment as a photographer, and it got me mixing things from scratch whenever possible. I also like the opportunity to learn how the individual ingredients work.

If I understand you correctly, while the ice cream is churning I should periodically take the temperature and when it is -5C, transfer it to a freezer container and put it in the freezer? I have a Thermopen so I can get quick readings. Would this hold true for sherbets and frozen yogurt too? If I understand you correctly, while the ice cream is churning I should periodically take the temperature and when it is -5C, transfer it to a freezer container and put it in the freezer? I have a Thermopen so I can get quick readings. Would this hold true for sherbets and frozen yogurt too? You don't want to take the ice cream out of the machine before it looks right. The idea is to refine your recipes so they will reach the right hardness and volume at the ideal temperature. I take the temperature of the ice cream when it starts to look finished ... this will tell me if it needs to go another minute or two. But more importantly it gives me feedback about a recipe. If the ice cream is hard enough but the temperature is high, then the recipe could use more freezing point suppression. Or if the temperature is low, it could use less freezing point suppression. You can also use drawing temperature to get feedback about the recipe's whipability. A significant part of ice cream's texture is from whipped cream. This is the foam component. Conditions need to be right for the fats to whip properly. The mix needs to be aged at least several hours at a cold temperature for the fats to crystalize. There also needs to be adequate emulsifcation in the mix (if you're using any eggs at all, this takes care of it). Stabilizing ingredients tend to enhance whipability. So, if you get to the ideal drawing temperature and the ice cream hasn't gained the volume you'd like, this is a hint that the fats weren't properly crystalized, or that the mix is understabilized. If you have get too much volume, it can mean the mix is overstabilized. Different machines also do more or less whipping, and if you use a Kitchen aid attachment, the variable speed can be used to adjust this.

Nonfat solids, especially sugars, have a much more pronounced effect on hardness than the fat level. Fat actually has no freezing point suppression ability at all; it only effects hardness by its whipability into a strong foam, and by how hard the fat molecules themselves crystalize. This latter question mostly becomes an issue when you have fats that harden a lot, like cocoa butter. When your ice cream only has milk and egg fat, you'll find that the fat percentage makes little difference compared to the other solids. A great way get your recipes under control is to pay attention to drawing temperature. This is the temperature of the mix when it's whipped up to the texture and overrun level you like. I keep a thermopen style thermometer by my ice cream machine and check the temperature when I think the ice cream is ready. All my recipes are designed to draw at -5°C / 23F. This is a good temp to aim for. It gives a good texture at serving temperature, gives good resistance to ice crystals growing, and guarantees consistency from one flavor to the next.

It just sounds like sugar crystalization. It's possible that the flavors causing trouble have enough naturally inverted sugar to prevent the issue. Not sure otherwise why you'd be getting it sometimes and not others, except maybe if your freezer is going through wider than normal temperature swings. If this were the case you'd expect to get a lot of iciness and not just sugar issues. The easiest solution to sugar crystalizing is invert syrup. For sorbets I aim for sugar in a ratio of 65% sucrose, 25% dextrose, and 10% trimoline. Total sugars are about 18% of the total mix. These percentages include sugar from any fruit ... so I use online tables to modify the added sugars depending on the fruit I'm using. Stabilizers do a great job modifying textures and preventing iciness, but I don't if they're effective against sugar crystalization.

You don't have to worry about the flavor of fructose when the blend of sugars is 10% trimoline. I promise. Blindfolds and a wager Invert syrup is around 30% sweeter than sucrose, but has 90% greater freezing point suppression. Dextrose has high freezing point suppression as well, but has about 30% less sweetness than sucrose. Having a sweeter sugar in the mix allows you get your desired sweetness with less sugar total. Unlike the dry sugars it helps stabilize the free water in the recipe and it helps prevent crystalization of the sugars. It is especially helpful in any recipe with dry ingredients like chocolate, nuts or nut pastes, or dried fruits. The ratio of saccharides that I suggested is comparable to the ratio that exists natually in many fruits. I don't want to get sucked into an absurdist Defence of Fruits, but I will suggest that their sweetness tends to taste natural, if nothing else. Keep in mind that honey is mostly invert syrup. I think it tastes pretty nice.

Lustig's fructose rants strike me as highly suspect. He has come under a lot of criticism in the research community for basing his conclusions on (other people's) studies that are of poor quality. Even so, his peer-reviewed research doesn't make claims that are as bombastic as the ones he makes publicly. Beware of researchers who make melodramatic cases directly to the public—most are quacks. Lustig is not a quack, but he's become a zealot on an issue that has virtually no other scientific support. I don't think anyone outside the soft drink industry will dispute that it's a good idea to cut down on sugar. But to demonize it as poison, or to single out and demonize the monosacharide that we're most evolved to eat—I don't think he or anyone else has made that case. Eat less ice cream. But make it good! This means using the sugars that make it good.

Bojana's exactly right. And no need to worry about "extra fructose." Invert sugar has the same amount of fructose as the table sugar it's made from. I have never seen real evidence even hinting at health (or other) reasons to avoid it. Beware the pseudoscience of the blogosphere! If you were ever to find a real reason to reduce fructose, you'd want to avoid fruit.

Here's a rough guideline for sugars that I find works well. I like the total sugars to be 14 to 15% of the recipe by weight. The breakdown is roughly 65% sucrose, 25% dextrose (powdered glucose—not atomized glucose), and 10% trimoline (I make my own invert syrup ... it keeps a long time). This formula gives a final ice cream that's a bit less sweet than store bought ice cream or most home recipes, but that has ample freezing point suppression. There's no need for adding alcohol to the mix, or for serving at overly warm temps. I formulate this for a drawing temperature of 23°F/ -5°C (this is the temperature at which you remove from the ice cream machine), and a serving temp of 6° to 10°F / -14° to -12°C. It's also more resistant to iciness than a comparable recipe made with all sucrose.

Venting the heat of a commercial range is probably only a problem if you get one with lots of burners. It's the total BTUs going into the air that matters. I don't think you'll have a problem with any 36" range. Most likely, well before you got to the point where you couldn't ventilate the heat, you'd get to the point where you don't have enough gas supply. The big daddy commercial ranges expect (I think) a 3/4" gas hookup. The bigger pipe will deliver gas (and energy) at over twice the rate of the 1/2" pipes standard in home kitchens. A bigger issue is lack of insulation at the back. You need some kind of masonry firewall, or a ton of wall clearance, as Budrichard says. Sheetrock is not recommended. There will also be more hot surfaces on the outside of the stove that a kid could get burned on, and there's potential of setting cabinetwork on fire. you don't want wood things butted up against the thing like you would generally have in a home kitchen. It will also be about 6" deeper than the countertops.

I'm in the habit of using a bowl over a saucepan of water. Water has never been an issue. Just keep it out of the chocolate. Every pastry chef I know uses a microwave. It must work well. If you're paying attention and have a responsive pan you use direct heat. I realize every cookbook says that doing so will cause a kitten to die. I'm just not often in that big a hurry. There are other things to do while the chocolate melts.

My custards don't thicken until around 185, but I use about a third as many yolks as what most recipes call for. I've read (but haven't tested) that the lower the yolk concentration, the higher the thickening temperature.