Tuesday, August 20, 2013

beef rendang sous vide 70degC 24 hours

Arduino sous vide beef rendang, using beef short ribs and cook for 24 hours at 70 degC.

"Cooking beef rendang can be time consuming and tedious" from wikipedia. Indeed, this is true.
 I remembered many many years back i was helping a makcik (auntie in malay language) to prepare this dish at my house. My job is dead simple. Stand in front of the gigantic kwali (a very deep wok) that is set upon wood fire and keep stir-ing with an apparatus that looks like a wooden oar. Still can't visualise?  refer to the picture below on how it was done! picture taken from the internet.

BBC food has a recipe to offer on cooking beef rendang. Look at the amount of time needed to stand in front of the stove to constantly monitor the cooking.

My methodology is simplified to the core.
Step1. get some beef short ribs. I got mine from smithsfield market at £3.7 per KG.
Step2. get a bottle of yeo's rendang paste. I stumbled on a few bottles at tesco with reduced price at 1quid or so. Needless to say, i bought all of them.

Step3. Smoother the whole bottle of beef rendang paste with the de-boned beef short ribs cut into 2cm x 2cm. This is a good time to season to taste. I added 2 bay leaves, 6 cloves, 1/2 TBSP of sugar and 1tsp of salt to the mixture.
4. Sous vide the entire package at 70degC for 24 hours. No constant stir-ing, no standing infront of the stove for hours, no burning of your facial hair from the heat. Just sit back, relax and forget about it for the next 24 hours. *do whatever need to be done i.e write my thesis! lolx*

5. I sous vide the beef rendang at 6pm the day before. So it will be ready by 6pm the next day. The time is just nice for me to have dinner when I am back from school.
6. I like my beef rendang with rice. Beef rendang goes well with any form of carbohydrates. Rice, bread, noodles, pasta, etc.
7. The texture? comes with a bite and yet melt in your mouth tenderness! the beef fats are rendered, tough proteins are denatured through sous vide. The rendang gravy is so good, momentarily i forgot what my name was while savouring the flavor. Given the fact that this cut of beef is tough and dirt CHEAP. I reckon the end product eclipses the £,time and effort needed to produce it. oh wait... is there any effort involved?! If considering waking up at 6am to get the beef short ribs as an effort, then that is one huge effort involved. hahahhah

still pink!!!

Monday, August 19, 2013

worth the wait for sous vide 48hours 62degC beef short ribs

Arduino powered sous vide of course.

sous vide the beef short ribs for 48 hours at 62degC. Beef is seasoned with pepper and bay leaves only.
beef short ribs, yorkies, crispy potato, coleslaw. sauce made from beef au juice.

fresh out of the water bath, looking pale.
sear on high heat for 60sec each side.
cherry blossom pink!
wash it down with home made pseudo champagne aka sparkling wine. although the wine is going at 2/3 discount, still palatable. 

Sunday, August 18, 2013

glutton's arduino sous vide beef short ribs 62degC 32hours

I went to smithsfield market yesterday morning to get some beef short ribs. I got myself some decent short ribs at very decent price, despite the market is closing in 20mins time.

Long story cut short. I experimented with a piece of the short rib, seasoned it with a dallop of oyster sauce, some black pepper and a tiny dash of sesame oil. Popped it into my arduino sous vide setup at 1000 Friday and it supposed to be ready in 48 hours time....

Staring at the short ribs in the cooker while eating some stale bread with expired cheese for dinner after a long day, is really depressing. The inner glutton strikes back! The rest was history.

62 degC at 32 -ish hours
look at the cherry blossom red. beef was cut using a butter knife. My poor santoku knife was decommissioned; a fateful clash when the metal meets with the bone. 
short ribs au juice is used as stock base for rice vermicelli. 

If you wonder how much per KG for a nicely trimmed and packaged short rib cost in major retailers?

Friday, August 16, 2013

arduino sous vide beef short ribs 62degC 48 hours

Woke up late and made a last minute mad dash to smithsfield meat market with the lads in tow. thank goodness we still able to get access. 
MEAT GALORE! short ribs, sirloins, lamb chops, kebabs, burgers,pork chops,pork hocks, etc. the regular size coffee cup is the reference point.
finally, i get to do some beef short ribs. I did spent a lot of time drooling over pictures and videos of it over the Internet. Doing it rather than watching it is a total paradigm shift.
this beauty is at £3.7 per Kg at smithsfield market. I think it is at £9.xx per Kg at major retailers.

arduino sous vide setup, 62degC for 48 hours.

my pot is too small to fit 2Kg at once. beef rendang got to wait till next time! it will be sous vide at 85degC for 24 hour

my poor santoku knife :( it is my only knife

Monday, August 12, 2013

arduino sous vide rack of lamb

I came across a rack of lamb that is destined to be reduced at sainsbury's earlier today. Rack of lamb is usually priced at £19.90 per KG, or £9.xx per package with 4 rib bones. lucky me, i got it at 4quid something!!!

Rub the rack of lamb with rosemary, pepper and some salt. vacuum pack it. I am using my home made vacuum sealer.

sous vide the package at 56.5 degC for 2-4 hours.

Remove the rack of lamb from the bag, pat dry and dress with olive oil and then give it a good sear on a very hot grill at 60sec per side.

Thursday, August 8, 2013

tuning PID for arduino sousvide

Often I came across people asking me on how to tune a PID setup. The setup I come across are mostly to regulate temperature, but with very different heating appliances. It really took me sometime to do the step by step on tuning and the process can be quite tedious. No 2 home made sous vide cooker are the same. Using the exact same setup as another with the exact same PID values the end results maybe vary. Hence, tuning is required.

Recently i came across the PID auto tune library on the arduino website. It is a nifty library to help to tune the PID with a command send via serial line, wait for some period of time (mine took 4 hours and still counting), then the auto tune will return 3 parameters: P , I and D that are suitable for controlling the close loop system at hand. I have used the auto tune with my arduino sous vide setup, code is attach at the footer. Then it strikes me, why not just tune by hand. PID controller is not that difficult, as compared to the kalman filter AKA LQE (linear quadratic estimation) type of control system.

This links provide some details of the PID and demonstrates Zigler-Nichols method for tuning PID. Tuning by blindly guessing the P, I, D parameters,  can be quite difficult and unnecessarily tedious. I am interested on the how to tune by hand by observing the characteristic unknown system. A few PID features to bear in mind that gives a good close loop control. 0. the set point 1. the rise time, 2. the time to settle, 3. the error rate/compensation; that correspond one way or the other to the P, I and D parameters. 

What we want in our sous vide is a fast rise time to the set point, e.g rise to the ideal temperature quickly; fast settling time, e,g the temperature do not fluctuates too much when approaching the set point. As a general guide line, an increase of P value will decrease the rise time; an increase of D value will decrease the settling time. Sounds good isn't it? At some point, I would ponder. is PID is really needed for the sous vide or a PD is generally sufficient?? As for increasing the I value, the error rate will decrease.

So, where to start tuning? Before starting to throw in random values into the code and spent the next few days trying to find the perfect value, let's make some educated inferences.

firstly, take note of the heating characteristic of your cooking vessel. I am using a slow cooker that comes with a ceramic pot. One particular characteristic of the slow cooker. The heat is dissipated slowly; the reverse is true to. heat is accumulated slowly. This feature is really forgiving for sous vide cooking since what we need is actually to maintain the temperature at a certain point and hopefully it will hold at +- 1degC precision.

I observed my slow cooker on full power to heat up would take 25secs per 0.1degC or 1min 0.24degC or 5min 1degC. This means that if I randomly enter a very large P value it will still take 5 mins to heat up 1degC, but the reverse of this; turning off the power for 5 minutes will lose 1degC is not true.. As compared to a setup that uses heating coils; randomly throwing in a very large P value will have an effect that is devastating for the sous vide. slow cooker is much forgiving with large P value than the heating coil. Dissipation of heat is affected by room temperature, cold room heat dissipate faster.

Next few paratemers, the time taken to settle, amount over shooting the set point, and error recovery. this 3 parameters are different, but somewhat related to the input parameter. If the input device is not reliable with values read in fluctuates wildly, no amount of tuning can save that. So, it is very important to ensure that the temperature acquisition device is constantly stable for a reliable PID tuning. temperature reading with precision of 1 decimal places is good enough for PID used in sous vide cooking. The precision will affect the computation of the error rate.

Here comes the tuning by hand modus operandi
Set a large P value lets say 500, a very small I value let say 1 and choose a mid value for D let say 100. Observe the time taken to reach the set point. Observe the amount of degC overshoot from the setpoint and also observe how long it takes to throttle (turning on and off of the SSR) the current, finally observe how long it takes to settle at the set point.  Always start with P value. If it takes very long to reach set point, increase P. then the D value. If it takes very long (i have decided +- 1degC for more than 5 minutes is very long; using the observation mentioned above) to settle at the set point, increase the D value. For a PID to settle within 1second time frame with my slow cooker setup is unrealistic and difficult to achieve. Finally the I value. If it overshoots by a large amount before throttling of current occur, increase I. Repeat this process until a satisfactory result is obtain.

Happy pouring cold water into the vessel, observe the temperature changes and modifying the P, I, D parameters.

Thursday, August 1, 2013

Dangerously life threathening method to poor man's drinks carbonation

WARNING: Risk of explosion from charging compressed CO2 into the P.E.T bottle!! 

I have a dream; a dream I can make a bottle of £4.19 white wine from tesco to taste like moet (champagne/sparkling wine produced in a certain region of france) just to help me keep my cost down for asking human over for dinner. I tinker with the idea of inducing nano sugar particles into the white wine to give the sweet note of sparkling wine; while forcing compressed CO2 into white wine to imitate the carbonation from the luxury of secondary fermentation. My dream was close to reality; until I took a £500 hit to my already badly beaten wallet after an unexpected visit to the dentist for root canal treatment. No alcohol in due course of antibiotics.

8gram CO2 charger/cartridge

My dream is simple. An 8gram CO2 charger/cartridge, loaded into a S30 valve with piercing pin, thus compressed CO2 will carbonate the liquid content in a cheapo P.E.T bottle. The risk is high. The P.E.T bottle will expand rapidly and possibly rupture before the pressure release rubber kicks in at 10PSI (assume is new rubber) from the S30 valve; killing the operator or missing a digit/losing an eye. But a lad so poor, he can only lose his life in the name of cheap but "controlled" experiments.

NOTE: Do NOT screw the P.E.T bottle's cap tightly shut when carbonating with this ghetto method. Give some more room for CO2 to escape. Trade your safety for a fully carbonated drink? NEVER!

The risk of carbonating in a bottle is real.
the 20quid Twist&Sparkle is wonderful, but certain model is recalled back in 2012.
This is a first hand account of the exploding home carbonation kit.

So the 120quid perlini, the dream equipment of a home chef to impress his/her date over a drink. The ultimate kit that uses similar concept and widely used by molecular mixologist. IMHO The price do make up the difference for safety!

My dirt cheap setup only cost 12quid for the s30 valve with piercing pin and also a charger holder, which can be adapted to a myriad of vessel.

I infer that if the volume of a PET bottle is large enough (say 2L soda bottle) and the PET walls are strong enough to hold pressurised air from an 8gram CO2 charger (soda are carbonated in the bottle, albeit regulated PSI); I should be "safe".

dry run, no carbonation yet. Still contemplating to lose a digit, an eye or my life.

I have been hunting around for large soda bottles but no luck still. So I have to improvised with a 900ml bottle, with the cap not tightly shut while carbonating.

carbonation, with the cap not tightly shut

Ahhhhh...carbonated apple juice. enjoying the fizzz with all my members intact. phewwwwww........ Drink, in the name of controlled and safe experiments!

New mod to direct CO2 into the liquid

maybe it is time for me to acquire a proper set of ISI siphon to achieve god mode results in safety?

guess what i found at the museum of london?

1930s' carbonator.

i did carbonate some cheapo white wine over the weekend....fizzy, but the taste.... blehhhhhh

poor lad's vacuum sealing hack using vacu vin pump and wine stopper, and 3D printing

It has been two or three years or so i have been dabbling in sous vide cooking with my hackish sous vide cooker. The PID controlled cooker is only one half of sous vide; the other half is with the vacuum sealing. It is like the yin and the yang in sous vide cooking. For years I have the cooking part, as for the sealing part, I just make do with water displacement technique. What makes sous vide so prohibitively expensive to enter is the upfront equipment cost for the cooker, and not forgetting the vacuum chamber for packing and sealing the food. I shall not dive into the details of the benefit of packing food in vacuum for prolong shelf life.

As for the sealing portion, I have gave some serious thought on heat sealing, experimenting with the temperature for the plastic would melt but will not burn. Somehow, the thought of toxic from burnt platic made me drop the idea of heat sealing. Afterall, there is still room for scientific research to prove the hypotheses of melted plastic will have an adverse effect on human. Thus, I shall stick with mechanical sealing if possible

I have been hacking for a vacuum sealer for some time. As an engineer, I broke down this problem into 2; the vacuum portion, and the sealing portion. For the vacuum portion, I have hack a usb vacuum drive  , and BBS a vacuum pump to use with my own vacuum chamber made using 1" thick polycarbonate sheet, a frying pan, and used bicycle inner tube.

As I give a lot of thoughts on how to build the vacuum sealing solution, I am hitting it from an engineering point of view. Which potentially can be a blind spot for an elegant and simple solution. I knew I have been hitting that blind spot, because the solutions that went through my head is getting intrinsically complicated than ever. When a engineer sees a problem, he/she solves the problem. Human or computer problems alike. Hence, do not let engineers handle human relationships or potential love affairs.

Few days ago, the design and idea just struck me. What I really need is a cheapo and hand operated vacuum pump, a check valve (to ensure single direction air flow), and a "double bag method" for me to take my own sweet time to vacuum seal the packaging mechanically via zip lock bags, the bags I have been using quite a lot. Since I already have a vacu vin vacuum pump (I hacked one using a  £1 bicycle pump, but it does not work as well as expected), vacu vin wine stoppers (essentially a proprietary single check valve with pressure release). What I need to make the whole thing work is to fabricate a stand of some sort to house the vacu vin wine stopper (check valve).

Just two days ago when I was shamelessly stealing ideas from thingiverse.com and I came across this design http://www.thingiverse.com/thing:105842 and straight away I knew i have to remix this as a hack for vacu vin pump and stopper. the remix is available here: http://www.thingiverse.com/thing:126297 Courtesy of the 3D printers at institute of making, fabrication of the stand is in a jiffy.

The rest are just history.

close up view of 3D printed base and vacu vin wine stopper.

puncture a hole on the bigger outer bag where this hole will be aligned to the hole on the 3D printed base. plug in the vacu vin wine stopper. Insert a smaller bag with food and partially seal the zip lock. seal the zip lock of the outer bag.

Pump away with vacu vin pump. Good exercise I would say.

not true vacuum, but nonetheless simple and elegant design as a solution