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Posts posted by DocDougherty

  1. I was wondering if all the folks with an Auber Instr. (or other) sous-vide set-up could post their basic setup and their thumb's-up thumb's down on the unit.

    It seems like everyone is pretty happy so far.

    Is there anyone unhappy with their purchase?

    Thanks in advance!

    I have tested it with a small rice cooker with good results. What I discovered was that if I put the rice cooker into "keep warm" mode, full power is just enough to hold 140°F which gives me an alternate way to more tightly control down around 130°F.

    To date, my only concern is with the fragility of the sensor wiring. It does get crimped where it enters the cooker so I need to put some spacers in to keep the lid from resting on the wires.

    I am going to use it to control a Hot Tray which has a tendency to overheat. But I am still looking for a good way to thermally couple the sensor to the surface with a low thermal inertia.


  2. I have a large ham from a neighbors pig (organic, free range, outdoor, home brine cured and then soaked to remove excess salt). I would like to cook it sous-vide.

    Any idea as to time/temperature?

    I'm inclined to say its just a large piece of meat and use 60C for 18hours or so, but could argue for anything from 55C to 75C.

    Needs to have time for the collagen to dissolve


    I would be inclined to go a little longer than 18hr, but the temperature is about right (actually I would smoke it with apple wood for 12 hr@ 250°F, then @225°F until it reaches a core temperature of 190°F - about 23 hr total, but this is the sous vide forum so you get the sous vide answer). I do Tri-tip for 24hr@59°C and you are probably quite a bit thicker, so maybe 30-32hr. Others may have more experience with sous vide pork and thus provide more relevant guidance.


  3. I suspect I should have returned it to the cooker at 55C for (how long?) to bring it back to temp before searing it.


    In a case like that I would cool the sous vide tank down to 120-125°F with some cold water and after chilling the meat put it back in the tank and leave it until I was ready to sear. The chilling will stop the cooking of the meat and at a water bath temperature of 125°F it shouldn't go beyond medium rare. When you sear it, the outside will heat up but the inside won't receive much of that heat, assuming you are using a really hot pan.

    If it is going to be more than a couple of hours you might chill it as you did, and then put it back in the tank. For that I would just use Nathan's tables to figure out how long (selecting the right table based on the temperature difference rather than the end point temperature as Nathan suggested up-thread a ways)


  4. Yes, you can use a ziplock. No, its not really important have vacuum. You just want to get most of the air out of the bag and make sure its sealed well enough to keep the food in and the water out.

    And since you will always have some trapped air which can float the bag, it is helpful to put a handful of glass florist beads into the bag to keep it under water.

  5. I was directed to this forum by a search for Liege waffles, but either I missed it or just the waffle part was matched by the search engine. In either case, I am looking for some guidance on how to replicate the waffles that I rember buying on the streets of Brussels. Sweet, yeasty, chewey, dense. I tried some years ago to develop a yeasted waffle recipe but while it was OK, it was not a match to what I remember. And since I am about to start the quest again and I thought I would first query the expertise here before I bumble off on my own.


  6. the Foodsavers don't pull a powerful enough vacuum

    Perhaps I don't understand the basis for comparing the vacuum performance of various machines. A chamber type machine does not have to suck the air out through the very fine channels left by the cross-hatching on the inner surface of the bag (in fact a chamber machine can use the less expensive smooth bags), so when it gets to 1 mm of Hg, everything in the bag is at that pressure and the increase in pressure after sealing is due only to the ratio of free volume in the bag before and after returning it to atmospheric pressure. A Food-Saver on the other hand must generate sufficient vacuum to transport the residual air in the collapsed bag around the food and out through the vacuum port, and even with 1 mm of Hg at the pump, the inside of the collapsed bag has a somewhat higher pressure since it can never totally equalize due to the low differential pressure. But the bag is collapsed already and the pressure doesn't increase after the seal is made, at least until the bag goes in the water bath and the residual air begins to expand. Can somebody explain the relative performance of these two types of machines in a quantitative way?


  7. Do you think you can add a rheostat on a motor like this? Even the small ones say something like 2500 To 5500 CFM. Wow.


    The 2500-5500 cfm would indeed be a lot of water (19,000 - 41,000 gal per minute), but it is actually the air flow rating through the swamp cooler rather than the volume of water that goes through the pump. The smallest size is all you are likely to need as it still will move a lot of water. Here is a link to a typical pump (Swamp Cooler Pump). Since they are designed for only about 36" of head, even a small flow restriction will drop the volume substantially. A section of small diameter tubing would be enough if you can find compatible fittings to step down the diameter - then you can trim it back until you get enough flow; or you could put an end cap on and drill it out to a size that works.

    As for a rheostat to control the speed of the pump? I don't know. It depends on how the motor is wound. I would just use a flow restriction and not worry about an electronic solution. Besides the electronic control engineers learned most of they know from their mechanically inclined forefathers - and there is usually a cheap mechanical analog if you can just figure out what you need and find the right parts at the hardware store.

    My Lauda (E100 I think) has three speeds on the circulation pump, but I rarely use the highest speed in the 6" steam pan that I use for a sous vide tank.


  8. I'm picking up a pid unit that is designed for sv early next month and will be doing some testing. I'm going to be using a steam table for the heating source along with the pid and thermistor probe.

    One thing I mentioned earlier in the thread is how I might try an inexpensive aquarium circulator. I’m curious if they can handle the temps.

    I'm also thinking trying a simple aquarium air pump as the circulator.

    Another solution to consider might be a small swamp cooler circulating pump (which costs less than $20) in which the motor drives the pump impeller through a fairly long (maybe 10") vertical shaft. In a swamp cooler the pump impeller housing sits on the bottom of the sump and pumps water at a constant rate over shreaded aspen pads. The motor sits up out of the water. For sous vide you might have to arrange to suspend the pump in some way to keep it stable with the motor safely out of the water. For a shallow pan you could let the impeller housing sit on the bottom, and on a deep pan you could suspend the pump at the top of the pan and put a tube on the pump output that would send the water to the bottom of the pot (or anywhere you want it). Since all of these pumps are nearly constant speed and move a lot of water, you might want to add a speed control to throttle it back.

    I thought about the aquarium pump and had the same question about their ability to stand the temperature. I decided that I didn't want to do that test with a 120v power cord immersed in hot water. I think the air pump might work, but will probably allow air to collect under the bag(s) and float them, or trap air between them. I wouldn't worry too much about cooling the water with that little air. It certainly is less effective at cooling than taking the lid off.

    Let us all know how your experiments come out.


  9. Seal the fat-shake mix in a sous vide bag and cook in a water bath or other method at 180F/82C for 12 hours.  The fat can be poured off the top.  If you clip the top corner off the bag, you can pour the fat off pretty well.

    I really like the method, and it should work for duck fat as well as for lard. But just for safety reasons I might be tempted to chill the vacuum bag in ice water before trying to pour off the fat, but the fat is likely to congeal non-uniformly in ice water so maybe it would be better to actually refrigerate the bag until the fat is completely solid. Then it should be possible to cut off the bottom of the bag, drain the water, remove and dry off the fat, then trim off any residual gunk.


  10. I installed one of those on my electrical range more then a year ago and coudn't be more happy about it : it was not too expensive, can be used with about any pot and for a wide range of applications.  I can use it to make 40 C salmon or to make 72h short ribs and it does not take any space at all.

    Here is a link to the post I made about it a while ago.  PID modified stovetop


    Simple, elegant design, few parts, excellent documentation, fails safe (unless the SSR fails as a short, but that should be very rare), inexpensive.

    What is the rating on the SSR?


  11. WRT precision and accuracy... presumably the temperature sensors on these controllers are sufficiently accurate, if that's what you're getting at.  I still have a hard time believing that a bottom-heated system or a crock pot system controlled by one of these things wouldn't exhibit temperature variability to the tune of 5-6 degrees C. 

    You are correct that the sensors have little hysteresis and are also quite accurate, but the amount of temperature overshoot that you see in practice is proportional to the ratio of energy stored in the heating system (above the set point) to the energy stored in the water (assuming that the container is relatively light and the food is slow to respond). So if you are controlling a 1200W hot plate and it is heating a pot full of 20 lb of water, you might have 10 to 20 BTU of heat stored in the heating element when the sensor/controller turns off the power (assuming a bang-bang controller). That heat can raise the temperature of 20 lbs of water by only 0.5 to 1.0 °F. If you have the controller set to control to a 1°F tolerance, you have a compatible system. On the other hand if you have a large heater and a small pot of water, you could see larger swings in the water temperature. If you are trying to approach a linear controller performance, you could put a variac or an SCR/triac in the power line to the heater and after it gets up to temperature you could reduce the peak input power. This would mean that the heater will be on a larger fraction of the time, but the water temperature will not recover as quickly from a transient (such as adding food to the pot). Lots of choices. For a convection-driven system, you probably want to have some amount of constant heating at the bottom just to turn over the liquid in the pot.


  12. While not being a long time smoker, but a long time rib lover, the material in this thread has been a good read. I have been smoking ribs for a few months, and by the trial and success method have arrived at a process that seems to be repeatable and successful. This is for dry ribs. I discovered some years ago that wet ribs taste like the sauce while dry ribs taste like pork unless you put too much dry rub on:

    Baby back ribs

    Remove membrane, odd dangling bits, and bone chips

    Apply 1/4 to 1/3 c dry rub to each side

    Dry Rub:

    Mandatory stuff-

    2/3 c chili powder (Smart & Final - chili, cumin, salt, pepper, garlic)

    2/3 c New Mexico chili

    1 c brown sugar (if you like a stronger flavor use Indian gur - dried sugar cane juice)

    1 T kosher salt

    Optional stuff -

    1 t smoke salt

    2 T black pepper

    2 T cumin (toast and grind)

    1 T onion powder

    1 t garlic powder

    Wrap in foil and refrigerate overnight

    Remove from foil and cut to fit the rack in your smoker (meat temperature is about 48°F at the beginning of the cycle)

    Smoke with 3 oz of applewood (this will be different for different smokers but only smoke for an hour or two and use a mild wood - the smoke doesn't begin to stick until the surface of the meat is dry so perhaps less if you predry the meat before starting to smoke)

    Smoke for 6 hrs (4 hrs @ 250°F + 2 hrs @ 225°F) bones down or on edge, without opening the smoker. This may need to be a bit different for each smoker, mine is an AmeriQue, which is electric, well insulated, and with a PID temperature controller). If you have a probe in the ribs, the temperature should reach 180°F at about 4 hrs and stay there for the last 2 hrs. There is always a long period at around 160-165°F while the fat renders.

    Commercial rib joints with big electric smokers generally smoke at 225°F for about 4 hrs, but they have big heaters that get the temperature up quickly and sometimes also have convection fans to make sure everything is at the same temperature. You can do this in your oven (convection or conventional) but without the smoke - and it is quite good that way too.

    Try it. Change it as you need to. If the bones are falling out, reduce the temperature and humidity - as somebody pointed out up string humidity is what detaches the meat from the bones. If the meat is tough but the fat has all rendered out, reduce the temperature and increase the time.

    Keep good records. Don't make big changes in one step. Buy good quality meat. Enjoy.


  13. I'm interested as to what we think would be the minimum practical volume for a home water bath for sous vide, and I suppose we should divide it into two categories depending on whether the temperature will be equalized throughout the water actively, with a recirculator, or passively via convection. 

    To my thinking, you'd want to have a fair amount of space around the food, and in particularly between the food and the heat source, when using water bath that is equalized by convection.  With a recirculating water bath, should be less of an issue (especially if the heating element is in the recirculator).

    Ah yes - an interesting point for conjecture. But the minimum volume for what? A retail sous vide system with a tank and heater? Or the size of the smallest tank you want to use with a clamp-on circulator? I think the retail system is designed by the maximum size that somebody can store and carry to the sink to empty - maybe someplace around 40 lbs full or less than 4 gal of water. But with a circulator that can be clamped on the side of a 2-gal spaghetti pot, you can get by with a lot less water when you are just cooking a piece of salmon, maybe 1 gal. But to do three 3-lb tri-tips and have enough room for them without trapping them against the side or bottom, it may take 3 or 4 gal. Probably would want to do a focus group to figure out what the major drivers are perceived to be - but you would need experienced users to get valid results (unless you are interested in what sells rather than what is right).

  14. I agress that +/- 5C is a big deal, and the difference between raw and cooked or rare and overcooked.

    A crock pot might work if the controller was a PID (http://en.wikipedia.org/wiki/PID_controller ) with analog output and the food was on a rack with sufficient circulation space under it.

    Unfortunately most cheap remperature controllers are bang-bang on/off and that will cause large local temperature variations.

    For restaurant use the thing has to be chef proof, and that means things like splash proof, easy clean and with controls that lock. Fortunately many lab suppliers are now making food versions. I have one from Grant Instruments

    Thanks for the pointer to the Grant Instruments sous vide tanks. This is the first time I have looked at them. It appears that they have done the engineering quite well, what with a 1 deg control band, thermal convection instead of a circulation pump, heater on the bottom to drive the convection (vs on the side as with a crock pot), stainless all around and a relatively tight lid with no cutouts for stuff to pass through. Somebody else will copy this with an integrated plastic or powder coated steel shell and cut the price, but at $900 for a 3 gal tank it is not much less expensive than a new Lauda circulator. You certainly don't need 0.1C of accuracy for sous vide (the Lauda controls to much better than 0.1C after it gets up to temperature), but the flexibility of being able to use it in a big tank or a small pot, easy storage, etc. would make it my preference even if I was buying it new today. Luckily I don't have to worry about chef-proofing, but I understand the concept. The price point for a mass market sous vide system is probably around $300, which means that it needs to cost less than $60 to make which is quite a challenge if you have any custom parts. I think that is about where the Grant Instruments unit is (maybe less), but they are not attempting to sell it at Target or Walmart.


  15. hi guys I know this has probably been dicussed already- but what is a safe time/ temperature for chicken breasts? I have tried one hour at 64 degrees C, following a previous trudge through nine pages of posts,  one that I did see said; 51 mins @ 58.5 degrees C or something to that effect.....

    but the meat still looks pinkly juicy. I think that it looks fine, but maybe customers would object to any pinkness in chicken breasts. I worry about clostridium, as I am making a cook chill product (for a product development module for college.... I am not a danger to public health). I have tried doing low temp ie 60 degrees C/ 1 Hour, followed by a 'botulinum cook' or 1 min at 90 degrees C, there is a noticable difference in texture, however.


    Nathan is a minimalist when it comes to temperature. And he probably thinks I am overcooking them, but 153°F for 1.5 hr has proven to produce tender, juicy, non-pink chicken breasts. Turkey breasts seem to need 2 hr.

  16. way to bust out the charts, jackal!

    so it appears from looking at this lovely graph that my theoretical room temp starter, at or around 70, would be the least tangy of all temperature possibilities.

    that doesn't sound very promising. :sad:

    you can't start it cold, can you?  as in, in the fridge (please pardon if that's a stupid question, a lot of this still seems a bit like alchemy to me)?

    Others on this forum and at http://groups.google.com/group/rec.food.sourdough/topics

    have convinced me that the two most significant variables for controlling the sourness of the finished loaf are:

    1. the percentage of the total flour that is in the starter when the dough is mixed (less requires a longer ferment, but produces a more sour loaf irrespective of the level of hydration), and

    2. having some whole wheat or rye flour in the mix to buffer the dough and allow the total acid to grow and add sourness before the pH drops below about 4.5 and shuts down the lactobacilus activity.

    My experience is that this is true irrespective of the average fermentation temperature - within the range of my kitchen over the course of the year (65F - 80F).

    Twenty percent of the flour in the starter produces a relatively mild loaf while five percent makes a more sour loaf. No whole wheat (or rye) will make a less sour loaf than 25% whole wheat, but I can't yet rationalize a particular fraction.

    Perhaps this is a case of following your nose to the answer.


  17. 2) I'm also getting a lot of noise and vibration from the circulator- I'm wondering if that's not partly due to the fact it's resting on the floor of my pan.

    Check to see if the circulator pump drive shaft protrudes from the bottom of the housing. It may be spinning on the bottom of your steam pan and that will be noisy.

    If this turns out to be the problem you can probably extend the height of the end-wall of the pan with a piece of appropriate material and a C-clamp. A chunk cut from a polyethylene cutting board or a Corian sink cutout should work, and a piece of 1/2" plywood would be a temporary approximation. Just enough height to get the circulator off the bottom of the pan.



  18. Your results are very interesting, and show the great amount of variability in the FDA regulations.

    The 2005 FDA Food Code, Chapter 3 has a table that is used for most meats - the lowest temperature is 130F and the time is 112 minutes - 

    here is the link - look at page 74 (page numbers on bottom of each page, not the PDF page number).

    This is clearly contradictory with your table, which goes down as low as 120F, and which calls for 30 minutes at 130F.  

    So, who to believe?  Which is correct?


    Here is an interesting research paper with real data on thermotolerant E. coli O157:H7. It shows that 62 min at 58.2C is adequate to give five orders of magnitude reduction in E. coli in pepperoni, even for bacteria that were adapted to a low pH environment. There is lots of other material with similar conclusions in the references.


    edited to fix the link

  19. I’m wondering how important the vacuum part of sous vide is.  It seems to me that using a Ziploc bag, getting most of the air out, and suspending it in a temperature controlled water bath might be enough to create “poor man’s” sous vide (being careful to avoid leaks into the Ziploc bag).  If one were to make sous vide for immediate consumption I don’t see what vacuum packing adds to the process.


    I think you get it. And yes it is possible to do as you say, even letting the pressure of the water bath push out most of the residual air from a flimsy bag. But you will still have some residual air, and the bag will tend to float, and you will have problems with bags that leak, but yes you can do it. For immediate consumption.

    If you wrap the food in Stretch-tite and then double bag, and put a handful of florists glass beads in the outer bag to add some weight and keep it fully submerged, and you are both careful and skillful, it will come out perfectly.

    And after doing this a few times you will go buy a Seal-a-Meal or some other inexpensive vacuum machine, but by then you will be convinced that you really want to do sous vide with higher confidence and less work so it will seem a bargain.


  20. Dallas Texas

    India Palace

    12718 Preston (in Preston Valley shopping center at I-635, next to Chili's)

    outstanding food, good service

    Zyka (Hyderabadi? cuisine)

    100 S Central Expressway #? (Richardson Heights mini-mall) a few doors down and to the right from Udipi Cafe

    This is on the Southbound side of the I-75 service road, just North of Spring Valley

    quick takeout or bare bones eat in - good food, fast service, very affordable

    my choice for a quick meal - try the chicken biryani

    (same family also runs Zyka in Atlanta which I have not tried)

    Udipi Cafe (South Indian vegetarian cuisine)

    100 S Central Expressway #35

    nicely appointed, excellent food, moderately priced

    Saffron House

    5100 Beltline Road, suite 728

    Addison, TX 75254

    many specialties, quiet, excellent food

  21. I notice that most sourdough formulas specify the use of non-metal bowls.  Some experienced bakers I know who have been producing excellent breads for many years say they have used metal bowls without problems.  Does anyone know the science or reason behind this proscription of metal bowls?  Does it affect flavor or texture?

    I have read that metal bowls conduct heat "too well" and thus cool off or heat up the dough more (and more rapidly) than one might like. That said, I use only metal bowls (stainless) and have no problems that I can tell.


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