Cooking Theory

Can anyone hypothesize if:

Corn is generally cooked at 190 degrees for an hour or hour and a half,,,how much faster could corn be cooked if temps were increased to say,,,247-248?

Evidently the starches in corn are rendered ineffective at 311 btw.

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Comments

  • At 250f, a few minutes at most.

  • edited August 4

    Saw a system on line somewhere that used a 500L slurry tank. On the continuous feed (steam injection) the system is able to fill a 16000L holding tank per day.

    Also saw a mini system with a 15 or 20L slurry pot that pushed corn starch slurry through a heated cylinder that was about 16 inches long. The corn starch slurry was completely gelatinous within a few seconds.

    So I'm thinking a 500L slurry tank with agitator and with a way to meter in flour, water, and Alpha Amalaise.

    Then pump the slurry on a continuous basis to a steam fired heat exchanger. Basically a 7' long tube in shell HX with a center tube that is about a 4" diameter. In the center tube there will be a static mixer that easily inserts for easy cleaning.

    Pump speed will be predicated upon the discharge temp out of the cooker HX.

    Gonna draw that up.

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  • edited August 4

    The HX cooker will be oriented vertically so that the slurry can be easily discharged into the top of the tun.

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  • Can discharge into a larger heat exchanger to drop temps closer to 150 before discharging into tun.

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  • We are still working on the continuous masher.

    Works well, need more steam.

    We changed up the lobe pump to a slower pump with more horsepower.

  • edited August 6

    Approximately like this. But with the tube in shell HX unit rather than live steam injection.

    image

    image.jpg
    800 x 501 - 43K

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  • @grim said: We are still working on the continuous masher.

    Works well, need more steam.

    We changed up the lobe pump to a slower pump with more horsepower.

    VFD on that?

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  • edited August 6

    Yeah but we got it geared down to match the flow of the starch cooker. It runs 8gpm at the top end, 3hp pump, stainless lobe.

    Next up is to get a dosing pump to inject high temp amylase continuously.

    image

    image.jpg
    800 x 248 - 41K
  • Milling in at 16.6lb per minute with roughly 5.25gal/min of water, for a total volume of 7 gal/min.

    We've run the water as low as 3gal/min, and it's like extruding thick custard.

  • Works exactly like the diagram with a few mods.

    The slurry tank is directly connected to the hammer mill dust separator. We use water injection nozzles in the slurry tank to mix grain and water without clumping. The slurry tank is a modified keg, and it feeds directly into the 1.5" lobe pump.

    The lobe pump feeds the injector above. We are currently connecting a hose to the output and running it to the bottom port of the mash tun - since we don't have any kind of flash tank.

  • Do you have to add heat to the tun?

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  • edited August 5

    Yeah, I need to add multiple lengths of 10' tubing to increase the time under heat/pressure. Snake them up the wall.

    I also need a whole lot more steam.. Probably need 750-1m btu of steam at 7-8gpm.

  • I do sell 20' lengths of sanitary 2" btw.

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  • edited August 6

    This so far

    image

    image

    Inline Cooker vciew 2.jpg
    800 x 486 - 40K
    Inline cooker.jpg
    800 x 514 - 35K

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  • edited August 5

    So the whole point of our system was to be able to use the hammer mill without generating an absurd amount of dust.

    So the slurry tank is air-tight, or probably more accurate, under pressure from the mill blower.

    We are using the slurry line for conveyance. We don't need an auger or blower to move the milled grain. Otherwise, we'd just mill into the mash tun directly (dusty).

    You need a lobe pump after the slurry tank, in order to hit 250f, you'll be pumping against the steam back pressure, and the back pressure of the feed line to the tun. You can't control the pump speed, it has to pump in balance with the grain and water inflow rate. You can only control the temperature via the steam flow.

    Keep in mind, you will hit a limit, we found the limit. With only 15psi steam line pressure, it's fairly easy to build enough back pressure in the slurry line that you stop the steam flow, which is bad. Without a check valve, you'll push slurry back down the steam line, creating a real mess (this happened). Starch will gel up and set into a slug. Our steam guy is pushing us to just go high pressure, so all of this kind of stuff becomes trivially easy. This is why most starch jet cookers are spec'ed for high pressure steam. It's not that you need 50psi steam, but the slurry line back pressures are going to get high with a stiff mash.

    Unless the tun is held under pressure, the hot slurry will flash into a boil as soon as it passes through the flow restrictor into the tun. This is why we feed into the bottom of the mash tun, we can recapture some of this flash steam to keep the tun hot.

    We have no mixers on the slurry tank, it's not necessary if you are feeding water and grain at the set rate. Maintaining the feed rate balance into the slurry tank is more work.

    Static mixer after the steam nozzle inlet - this is to help ensure all the steam bubbles are thoroughly mixed in the slurry, no lumps, no bubbles to puke and splash in the tun.

    Like in a continuous still, the magic here is balancing all flows, water, steam, grain, enzyme - to hit the perfect temp and flow rate on the output. The milling or auger feed rate is a key factor here.

  • edited August 6

    @grim said: So the slurry tank is air-tight, or probably more accurate, under pressure from the mill blower.

    Wouldn't the water incorporation allow for an adequate vent (even though I didn't draw one in) solution? My assertion was to mill very fine in order to expose more surface area.

    @grim said: you'll be pumping against the steam back pressure, and the back pressure of the feed line to the tun.

    This is an HX. Back pressure should not be the same kind of animal no?

    @grim said: You can't control the pump speed, it has to pump in balance with the grain and water inflow rate. You can only control the temperature via the steam flow.

    The pump can not be synchronized with the milling part of the operation?

    @grim said: Unless the tun is held under pressure, the hot slurry will flash into a boil as soon as it passes through the flow restrictor into the tun. This is why we feed into the bottom of the mash tun, we can recapture some of this flash steam to keep the tun hot.

    Sure this makes sense.

    @grim said: Static mixer after the steam nozzle inlet - this is to help ensure all the steam bubbles are thoroughly mixed in the slurry, no lumps, no bubbles to puke and splash in the tun.

    This is not steam injection, so should not apply in exactly the same way. Static mixer is to insure equal heat distribution within the slurry.

    @grim said: to hit the perfect temp and flow rate on the output. The milling or auger feed rate is a key factor here.

    No doubt. Perfect (aggregate) temp is likely also heavily predicated upon process volumes as well.

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  • I'm liking what's happening here. I can see this is useable for any type of unmalted grain, even flour. That opens up a new world for whisky making and means distillers don't need to pay more to buy malted grains.

  • Abstract

    Continuous cooker prototypes of very simple design, using electricity as a primary energy source, were developed for the process of cooking and liquefaction of starch suspensions. Previous work on equipment using microwave dielectric heating has already been reported.

    Results of energy consumption as low as 330 kcal/kg based on starch content were achieved. Considering these results and looking for new solutions or engineering concepts, the authors have been investigating the possibility of using electric energy at 60 Hz for direct resistive heating, in which the starch suspension is the proper “resistor.”

    The most important results of energetic yield obtained until now, working in a continuous process of cooking–liquefaction, are not larger than 235 kcal (272 Wh)/kg based on starch content. These results were obtained using a commercial grade α‐amylase from B. subtillis, working with temperatures ranging from 70 to 75°C, and with residence times in the reactor not greater than 1.5 min. The experiments of saccharification and fermentation accomplished as a test for the efficiency of this heating technique gave good results (as with a conventional technique) and thus enabled us to proceed with the studies.

    Citing Literature

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  • edited August 10

    @Smaug said: These results were obtained using a commercial grade α‐amylase from B. subtillis, working with temperatures ranging from 70 to 75°C, and with residence times in the reactor not greater than 1.5 min. The experiments of saccharification and fermentation accomplished as a test for the efficiency of this heating technique gave good results (as with a conventional technique) and thus enabled us to proceed with the studies.

    Not corn cooking temps. But super promising.

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