DocDougherty

A couple of eggless trials to calibrate the thermal losses showed that they are more like 65% of the energy required to cook the egg and are dominated by heating up the container (in this case a 16 oz widemouth thermos liner) followed by conductive losses through the cap/seal. Because cooking time is quite long if you want to wait until everything gets to equilibrium, adding more hot water and stopping at a pre-calculated time seems likely to be an improvement. Two runs with eggs uncovered and then confirmed/quantified a major temperature stratification issue. With a 60gm egg, 198gm of boiling water, and after 25 min of undisturbed cooking time there was almost 10°C of temperature difference between the top and the bottom of the water column (61.5°C at the bottom and 71.2°C at the top). A needle probe showed 66.8°C in the geometric center of the egg so the yolk should have been (over)cooked. But when it was sectioned through the center, the top half of the yolk was solid (the top was marked with a permanent marker) and the lower half was liquid. On average the egg was cooked. So if this is going to work, there will need to be a mechanism to circulate the water (or the egg), and it will require some empirical modeling of the loss mechanisms which are a substantial fraction of the total energy required, and there will likely still be a desire to add a time component to get the precision. It might be possible to build the model that is well enough calibrated that a combination of end point water temperature and elapsed time correctly estimates the internal egg temperature. Another approach would be to drop an egg into a water bath at a higher temperature and transfer it to a lower temperature bath after a fixed period of time, letting the heat propagate both in and out to finish cooking the yolk and to stop cooking the white. While it is still a 3-D problem, a 1-D approximation along with a calibration term might be good enough to deliver what you want. Doc

That is a very clever notion. And I am tempted to immediately start an inductive experiment, but a little back of the envelope analysis says that it is quite sensitive to losses (conduction, container mass and Cp, convection and radiation, etc). Making the approximation that Cp for an egg is 1.0, egg mass is 60 gm (large egg), the sensitivity to the mass of 100°C water is something around 0.5°C of final egg temperature per gram of water, not including anything for the as yet unspecified losses or their dependency on T(water) or T(egg) or ambient conditions, or container specifics. So while it should work, the degree of precision may be a little tough to deliver. But I am going to try it anyway using a wide-mouth thermos liner and a double air gap for insulation and an initial assumption that the losses are about 20% of the total heat. Doc

Vengroff, Great work. Reminds me of Nathanm's original approach using Mathematica. I trust you are solving Gauss in 3-D with an appropriate step size, so perhaps it would be possible to expose the heat transfer coefficient as an input variable so that those of us with Lauda circulators can adjust the model to accommodate variable pump speeds (or for other complications that make it different from your assumptions about the equipment). Doc

Luke, Cool! How many firebrick of what size support the pot? Perhaps a few dimensions on one of the SketchUp views would help. Any issues with beveling the firebrick so that they fit together tightly? And what is the heat source? Doc

I like that technique. So if you are trying to make tadig (only) you should be able to fully cook the rice, toss it with some fat, spread it on a Teflon sheet and bake it at an appropriate temperature until it is all brown and crunchy. Sort of the rice equivalent of oven fries. The remaining question is how long and at what temperature. Doc

Theabroma, Thank you very much! Your description of the process of making tadig is the most lucid I have found. There remain two point on which I am curious. First, what is the purpose of the towel? Every recipe I have found requires it, but without a credible explanation of its function. Is it to seal the pan and retain as much water as possible? Or does it act as insulation to increase the temperature at the top of the cooking rice? Or does it act to wick condensed steam out of the pan so that it does not drip back and reduce the temperature of the rice that is cooking in the fat at the bottom of the stack? This second mechanism should speed up the formation of the crust and reduce the extent to which the rice on the top dries out. Or is a Turkish towel heavy enough to actually hold all of the condensed steam so that it does not drip back into the pan? Or something else? Second, what is the temperature at which the rice begins to brown? It seems to me that you should be able to do this in a well controlled oven after soaking and parboiling the rice. At its heart the final preparation is quite similar to a biryani and many of the same variations should be applicable. And with this bit of information I can probably make rice that is mostly tadig (which is what I want anyway so it becomes a route to both a productivity and effectiveness). Cheers, Doc

There is an excellent (award winning) paper on idli fermentation by an 8th grader at http://www.usc.edu/CSSF/History/2008/Projects/J0405.pdf which lays out the fermentation regimen and identifies the two principal components of the active culture as lactic acid bacteria from the Leuconostoc and Lactococcus families. These are not "yeasts" per se, and probably exist in the native urad dal (speculation on my part but a fairly short series of experiments would nail down the source) rather than the rice. The fenugreek seems to be important in guiding the evolution of the bacterial population to enhance both flavor and texture (speculation on the part of Ms. Guhan). I have demonstrated to my own satisfaction that you can innoculate a new batch (250cc) with a little(25cc)active culture from a prior batch and dramatically speed up the fermentation (down from 20 hr to 4 hr), so the native concentration of bacteria, while reliable, is quite low irrespective of the source. I ferment at about 100F for 16 - 20 hrs when I start from scratch, but there are still many variables to play with (ingredients and their ratios, times, temperatures, process steps, ...). I am pretty sure that you could ferment small batches (5cc) starting at 24 hrs intervals and have an adequate supply to speed up a larger batch when you need it. In a pinch (assuming you live in or near an appropriatly diverse neighborhood) you can buy refrigerated idli batter from your local Indian grocery for use as either innoculant or final product. Cheers, Doc

Because they have so much fat in them they freeze really well and can be reheated in a microwave. It works better if they get some dry heat from an oven, but I have been known to nuke a small one for 45 sec and be out the door. Pearl sugar will remain crunchy; Billingtons too; the C&H raw sugar wants to hydrate so the surface can get sticky (thus a little time in a 250°F oven to dry it out). I don't know how long they will keep at room temperature. I do know that you can leave one out overnight and it is still good with a cup of coffee in the AM. Doc

I am not sure you have to break down the protein in the gelatin. You might be able to simply dilute it to the point where the strength is inadequate to hold the gel together. My inclination would be to dilute it and add a shear-thinning hydrocoloid like Xanthan gum to thicken it up a little (and offset the dilution without adding shear strength). Doc

Chichi, It sounds like your starter dough is too stiff, so I would suggest perhaps experimenting with a little less flour or a little more milk or perhaps a little longer initial fermentation. I am assuming that you are using a strong bread flour, warm liquid, and letting the initial dough ferment for at least 30 min in a warm place to develop (mine more than doubles in that time because there is so much yeast). I have made them with both a KitchenAid K45 and a Pro-600 but it takes a heavy duty machine to handle the stiff dough (as an aside I will note that the Pro-600 is not my favorite and -in my opinion- not a well designed machine since the cooling fan is directly driven by the motor and supplies insufficient air to keep it cool at low speed and high torque). The incorporation of the butter into the waffle dough is very similar making brioche. As the butter goes in, the dough will break and it will also become quite soft. Just let it mix for another minute or two until it comes back together and then another minute or two to fully develop the gluten. Only then should you add the sugar. And when I use a high gluten flour I find that the dough is so stiff that I must incorporate the sugar by hand kneading. And don't overmix the sugar as it will dissolve and fail to deliver the crunchiness that makes this recipe so good. Since I originally posted the recipe I have discovered that I can make a whole (4 small squares) waffle by heating the iron to 420F (according to my IR thermometer), using about 420g of dough, keeping the heat up, and baking for about 5 min, but it is more difficult than making smaller waffles at slightly lower temperatures. Hope this helps. Trial and success is a wonderful way to learn. Doc

Kenneth, Both scallops and shrimp came out perfect. 59C is where I normally do fish, and it is very forgiving of leaving the food in longer than the minimum time required to bring it up to temperature (that is why I went there for the calamari too). The scallops were large (16/lb) and the shrimp was of medium size (30/lb). The scallops came out butter smooth and the shrimp was just pink with some resistance and great flavor (it was peeled and deveined before packaging for the sous vide tank). After cooking and chilling I quartered the scallops and cut each shrimp in half (bite-sized pieces). That way they reheated quickly in the wok after everything else was cooked. Everything probably would have been fine with only one hour in the tank. Doc

For calamari, two hrs at 59C is enough to get tender without being either tough or mushy. Actually it turned out to be mouth wateringly tender. It does not produce the slight crunch that I associate with fried calamari, but it does produce a great mouth feel that is very tender while letting the characteristic flavor come through. I may try backing off on the time to one hour next time just to try it out (how can I go wrong on an experiment that cost $1.57). There has to be some point where it is just done at a time less than two hours. The temperature (59C) seems right. I will post again when I get the timing to where I want it. Tonight I cooked shrimp, scallops , and squid at 59C for 2 hrs, then chilled them and stir-fried them in the same wok with onions, marinated mushrooms, blanched asparagus, charred, peeled, and brined red bell and jalapeno peppers, sugar snap peas, a little hot curry paste and a little hot mole sauce. Doc

This is prep for a stir-fry so thanks for the link, that is helpful. Mine are done cooking but have not been stir-fried yet. Doc

Calamari? I have not found any results or suggestions for cooking calamari sous vide. Does anyone have any guidance? I am going try some little ones (6") at 59C for a couple of hours and see how they come out. Doc

Some will tell you that this is too hot, but I do turkey tenderloins at 153F for 3 hrs with just salt, pepper, and garlic powder. Tonight I just finished a pair of turkey tenderloins joined together using transglutaminase to make a piece that is intended to allow slices of breast that are comparable in size with a real bird. Since they were about 3" in diameter I let them go 5 hrs@153F. Doc

Try C&H Pure Cane Sugar (Washed Raw) - available in almost any grocery store. It has big crystals which provide some crunch, but for a little bit more ($ and crunch) look at Whole Foods for Billington's Sugar Crystals (also available on the web at Billington Sugar Crystals). And if you have an IKEA store near by, some of them have pearl sugar in their retail food shop - but more expensive than Billington's. Doc

Since water boils at 212°F, you must have made a typo, or you are cooking at 5950 ft below sea level (on a 1976 standard day), or perhaps you are pressure cooking the ribs. If either of the latter they would truly fall off the bone before you could get them to the broiler, so the temperature must be much lower, perhaps as low as 180°F if they are still less than totally tender after 4 hr. How are you measuring the water temperature? If you really want to sous vide your ribs, try 185°F for 4 to 5 hr, but since there is no place for the moisture to go, you will be essentially doing a low temperature braise and I would expect the meat to slip off the bones about the time they are as tender as you want them. If your oven will reliably hold 225°F, just rub them and bake them on a rack over a drip pan for about 3 to 4 hr @ 225°F (less if you have a convection oven). If that is still not tender enough, take the temperature up to as high as 250°F the next time. If they are still not done to your satisfaction after 4 hr @ 250°F, add up to an additional 2 hr @ 225°F. Once you find a process that works for you, repeat until you find a better way.

Thanks for taking the time and effort. This seems to indicate that a typical FS leaves at least couple of psi of residual pressure in a bag, and I am pretty sure that a chamber vacuum machine leaves less. I am trying to relate this to the effective buoyancy of the residual trapped air and my observation that I generally need to put about a handful of glass beads in a large bag to keep it from floating.

Pounce, I think it only puts on the table a measurement from a reputable source. Personally I see little practical difference between 1 Torr and 100 Torr. In terms of atmospheric pressure, you are at least 100 Torr lower in NM than I am in SoCal just as a result of the altitude difference but that shouldn't make much difference in terms of the measurement. On the other hand if you have the instrument, it would be interesting to have a sense of how good the dry pumps really are in the commercial Seal-a-Meal type devices. In the past when I needed a decent vacuum I just salvaged an old refrigerator compressor and attached an upward coiling 3/4" discharge tube to recover the oil that gets pumped out. With a couple of Freon flushes it was good enough to recharge both auto and home air conditioners but never good enough to boil water at room temperature. Doc

How about a simple case: 3 ft of 1/4" vinyl tubing direct connected through an adapter to a vacuum gage or manometer. Measure steady state low-side pressure after 1 minute of pump operation. In my experience it is not so much how good the vacuum pump is, but how much air is trapped in the food by the pressure of the bag. If you are as careful when you set up to use your Seal-a-Meal as you must be when you cast a gold medallion, then all comes out OK. Crushing fruit with atmospheric pressure is perhaps interesting to watch, but once you get the gas out, the remaining water is pretty much incompressible. Doc

If you succeed with using something besides a Belgian Waffler, I would be very interested in your exact technique (dough weight, waffle size, time, temp, non-stick spray or not, tender or crisp, etc.) I had one batch where I think the iron was too cool to start with and tried to open the iron too early. The waffle split in two - and neither side would come out of the iron cleanly. It was a mess to clean up - made me glad I could put most of the waffle iron (except for the thermometers) under water to soak it off or at least soften it up. And I put a photo in with the recipe in RecipeGullet under Liege Waffle

Plunk, It looks like I am three years late to the party, but I have a well tested recipe to share - it hasn't changed in 6 months so I am declaring it "good enough". Major points: 1. Ferment the dough for 30 min before incorporating the butter and sugar. 2. Waffle iron temperature should be about 405°F so that the pearl sugar actually caramelizes - I use an IR thermometer to check the temperature of the iron since I am doing it on a stovetop. Liège Waffles (6 – 100g waffels, ~305 calories each/70 calories from fat) (Revision #13 – 16 December 2007) These are very close to the real thing – as close to the waffles that are served on the streets of Brussels as I have ever come (and getting closer at every revision). The secret ingredient is pearl sugar or an adequate substitute. You will need a mixer that can handle a soft dough (I use a Kitchen Aid) and a Belgian Waffle iron. The one I have is a very old Nordic Ware Belgian Waffler, cast aluminum with a non-stick coating and little bi-metal thermometers built in to each plate (I am told that the new ones don’t have the built-in thermometers). The following recipe is sized for ½ stick of butter, substitutes instant yeast for the fresh yeast, substitutes vanilla extract for vanilla sugar, adds some sugar to substitute for the vanilla sugar as a yeast accelerator, and increases the liquid by a little to account for the moisture that would be in the fresh yeast and the fact that one extra large egg is not quite big enough to stand in for 1 egg + 2/3 yoke. I have increased the flour by 10% (from 213 g to 234 g) to produce a chewier product that more closely replicates what I remember of the Brussels street waffles. The original recipe calls for butter or margarine and also a pinch of salt so the butter is intended to be salted butter (since margarine always comes salted) but it wants to have just a little more salt. If you use unsalted butter increase the salt to ½ t. 234 g bread flour 82 g warm milk or water (110°F) ½ t granulated sugar (to feed yeast) 2 t (6g) instant yeast 1 t cinnamon 2 t vanilla ¼ t salt 1 extra large egg 67g (one half stick) room temperature salted butter or margarine cut into 8 to 10 pieces [for higher fat version: use a whole stick of salted butter or margarine and delete the ¼ t salt] 142 g pearl sugar (now available at some IKEA stores) or a substitute (Billington's All Natural Sugar Crystals - available at Whole Foods, or C&H Washed Raw sugar - available lots of places) Weigh the sugar and set aside. Dissolve yeast in the warm milk to which you have added ½ t sugar. Let this sit for five minutes to get the yeast started. Put the flour, cinnamon, egg, vanilla, salt, yeast mixture into the mixing bowl and mix on medium speed until fully combined. It will be stiff dough at this point. Cover with plastic and let rest in a warm place for 30 min. Beat in the butter piece by piece; you do not have to wait for the prior piece to be fully incorporated before adding the next. At this point (for all purpose flour) the dough will be a stiff paste that coats the mixing bowl. Scrape the sides of the bowl and mix on medium speed for another two minutes. If using bread flour, the dough will behave just like brioche, just mix at medium speed for another two minutes. The dough should clean the bowl after about a minute but will continue to develop for another minute. Incorporate the pearl sugar, or sugar crystals, or raw sugar just enough to get it evenly distributed. With all purpose flour you can stir the sugar in, but if you use bread flour you will have to knead it in. Using a little flour if necessary, divide into six equal pieces, form into balls. Proof on a piece of plastic wrap on a cutting board in a warm place (100°F) for 15 min while you heat the waffle iron. [set a Wolf burner on Medium and preheat the waffle iron until the built-in thermometers point to the high side of the “Cook” zone – about 9-12 min., flipping it over every 30 sec] Cook in preheated waffle iron for 3 minutes turning it over every 30 sec You can do two at a time in diagonally opposed pockets but they will take a little longer to cook, and they will not be as dark brown as a single waffle unless you turn up the heat a little, and you will get an accumulation of caramelized/burnt sugar in the middle of the iron where there is heat but no dough. With four at a time (filling all four cells in the iron) you need to turn up the heat quite a bit or extend the cooking time. If anybody is interested in reading the original in Dutch, let me know. Doc

Liege Waffles Serves 4 as Main Dish. This recipe makes 4 - 290g round waffles in a square iron, each containing about 885 calories with ~203g calories from fat. They are very close to the real thing – as close to the waffles that are served on the streets of Brussels as I have ever come (and getting closer at every iteration - and this is Rev #17). The secret ingredient is pearl sugar or an adequate substitute. You will need a mixer that can handle a stiff dough (I use a Kitchen Aid 600 which I dislike intensely) and a Belgian Waffle iron. The one I have is a very old Nordic Ware Belgian Waffler, cast aluminum with a non-stick coating and little bi-metal thermometers built into each plate (I am told that the new ones don’t have the built-in thermometers). And even with the built-in thermometers I always use my Fluke 62 Mini IR thermometer to guarantee that they come out right every time. The original recipe was found without attribution on the web in Dutch and the poster was asking for a translation from Danish. It has morphed somewhat with translation and adaptation. The following recipe is sized for 1 stick of butter, substitutes instant yeast for fresh yeast, substitutes vanilla extract for vanilla sugar, adds some sugar to substitute for the vanilla sugar as a yeast accelerator, and increases the liquid by a little to account for the moisture that would be in the fresh yeast and fractional eggs. I have increased the flour by 10% (from 426 g to 468 g) to produce a chewier product that more closely replicates what I remember of the Brussels street waffles. You may have to adjust the liquid/flour ratio to adapt to your specific flour. The original recipe called for butter or margarine and also a pinch of salt so the butter is intended to be salted butter (since margarine always comes salted) but it still needs just a little more salt. If you use unsalted butter increase the salt to 1 t. You can substitute for the Pearl Sugar with equal weights of Billington's All Natural Sugar Crystals or C&H Washed Raw Sugar which is adequate but not totally satisfactory. I use 50% Pearl Sugar and 50% Billingtons when I have both. 468 g high gluten flour 164 g warm milk or water (110°F) 1 tsp granulated sugar (to feed the yeast) 2 tsp instant yeast 2 tsp cinnamon 4 tsp vanilla extract 1/2 tsp salt 2 extra large eggs 114 g (1 stick) room temperature salted butter or margarine cut into 8 to 10 pieces (for a higher fat version: use a whole stick of salted butter and delete the 1/4t salt) 284 g pearl sugar (now available at some IKEA locations) or a substitute (Billington's All Natural Sugar Crystals - available at Whole Foods), or (C&H Washed Raw Sugar - available more widely) Take eggs out of the refrigerator and bring to room temp in a small bowl of warm water. Slice butter into 12 pieces and lay flat on a piece of waxed paper to soften. Weigh sugar and set aside (284g of Pearl Sugar is a whole box). Dissolve yeast in the warm milk to which you have added 1t sugar. Let this sit for 10 minutes to get the yeast started. Put the flour, salt, cinnamon, vanilla, eggs, and yeast mixture into the KA600 bowl and mix with the dough hook at speed 2 until fully combined. It will be very stiff dough at this point. Cover with plastic and let rest in a warm place (100°F) for 30 min (it will at least double). Beat the butter in piece by piece (with dough hook and KA600) at speed 2; you do not have to wait for the prior piece to be fully incorporated before adding the next. If using high gluten flour, the dough will behave just like brioche (that is it will break and then come back together), just mix at medium speed until it cleans the bowl (about one minute). Mix in the pearl sugar, or sugar crystals, or raw sugar just enough to get it evenly distributed. It takes about 1 minute with the KA600 at speed 2 using the dough hook. Using a little flour, divide into four 290g pieces and form into balls (for a full 4-square waffle use ~475g of dough but I have found that it is hard to get a square waffle to be uniformly brown). Proof dough balls on a cookie sheet in a warm oven (100°F) for 15 min while you heat the waffle iron for about 9-12 min., flipping it over every 30 sec. Wait for the IR thermometer to indicate that the exterior surface temp of the iron is 420°F when you flip it over. Spray the cooking surfaces lightly with a non-stick spray about 30 sec before starting each waffle. For 290g waffles, cook one proofed dough ball in a preheated waffle iron for 5 minutes centered on the burner, turning every 30 sec. A waffle is done when the IR thermometer reads 350°F at the top center of the iron just after flipping the iron over. For 475g waffles, increase the heat a little and cook until the IR thermometer reads 350°F. Reheat the iron to 420°F (about 1 min) and re-spray between waffles. A finished waffle should fall out of the iron. If it doesn’t, cook it a little longer. Keywords: Breakfast, Waffle Iron, Dessert, Intermediate ( RG2126 )

How are you cooking pork ribs to get a smelly scum? And are you sure it is coming from the bones? Some folks parboil to cut down on cooking time, but more time is not all bad. SV will poach them in their own juice, but they have no color but gray, so to dry them out, color them up, and season them, you will have to do something after they come out of the bag. You also will have to adjust the time/temp to get the meat tender without having the bones slip out which means keeping it below about 160F (which seems to be the temperature where the collagen dissolves). I generally smoke them for about 4 hr @ 225-250F with a spicy rub. You can get the same effect without the smoke in a slow oven, and if you have a combi oven such as a Rational you can keep the humidity high enough that they don't dry out, though pork is generally fatty enough that the texture of the finished product is determined by the fat as much as it is by the retained moisture. There is a fine line between a slab of ribs that falls off the bone (or the bones pull out of the meat) and one that you can cut into individual portions but still have the meat be tender, juicy, highly flavored, and come cleanly off the bone when you eat it. Doc

I have found that chicken breasts work best for my family at 153F for 2 hrs (wrapped individually), but you can certainly go down to 140F if you want to. As for safety, I found a research paper by some folks in Ireland where they showed that at 60C (140F), the decimation time (the time required to reduce the viable bacteria population by a factor of 10) for the most virulent thermotolerant bacteria is about 17 min (I think they were modeling pepperoni production). Since you want to take the bacterial count down to less than 1/cc, this means you want to run with the food at a core temp of 140F for 7 decimation times. So, adding 40 min to get the core up to 140F and 7x17min at temp, you should plan for at least 3 hr. Above 60C, the decimation times come down very quickly. On the other hand, if the food is for immediate consumption and it was whole muscle meat and it has been well kept and is clean and is salted when you start, you can use a shorter time, but that is your call. Doc