The effect of ramp/soak times on efficiency

[philistine]

Hey Beer Dudes,

Last year I built myself a 3v HERMS rig (actually 4v) with PID controllers. Prior to that I was just using a 19l bev cooler as a mash tun with no circulation or tmep control and if I wanted to do step mashes, it had to be a boiling water infusion sitcho to hit step temps.
My new rig uses an auber 2352p PID to control the mash which recircs thru an external heat exchanger.
The auber 2352p is the ramp/soak model, so not only does it allow you to program temp steps, but it also allows you to program a 'ramp' time - which basically means, programming the time it takes to ramp from one temp to the next.

Anyway, so Ive been running the rig for close to a year now and have just accepted the fact that my average efficiency is around 65% - 70%, which isnt much compared to the 85-90% i was getting out of my previous rig. I shoudl also mention that every single brew I do now uses a step-mash (just because they are already programmed).

Apart from the differences in vessels sizes etc. which lead to water volume loss (dead space = brewhouse efficiency loss) I've just realised that the programs Im using (which I pinched from an old post from Cocko) probabyl result in very short mash times once you factor in the actual ramp time.
For example, on his "dry ale" program, there is a 40min soak at 63c, which then ramps to 72 over 10mins - theoretically giving roughly a total of 50mins of time in "mash range".
The thing is, the step before the 63c "mash range" is a protein rest at 52c. While the program jumps from 52c to 63c in a 1min ramp step, it actually takes around 13mins to get there, meanign that the total time spent in "mash range" is closer to 37-40mins).

Im just keen to hear from anyone else who uses ramp/soak controllers. Do you compensate for ramp times in your mashing programs/schedules?
My system can comfortably increase temp from between 1-1.5 degrees per min depending on flow rate..... so Im just wondering if I was to add extra time between protein (and/or other pre-mash temps steps) if it woudl increase my overall extract effeciency.

In other words, Im wondering if my current routine is leading to an incomplete conversion during the mash.

I hope that actually make sense! I was struggling to phrase this post a bit...

CHeers!

PS> I'll try and find Cocko's old post that had his PID settings attached and link it into this thread

 

[wide eyed and legless]

Is this it.

 

[philistine]

yeah, thats the one!

 

[Mr B]

The pid won’t start the timer until the temp is at the step temp, and I think you can set the tolerance for this (I.e within 1 deg of temp).

Ramping will take whatever time according to your system, so you can either set a really short ramp and the pid will wait for temp before starting the step timer, or you can set the ramp time to roughly how long it will take.

So, you should be getting the full step temp and time, efficiency issues could be something else

 

[Mr B]

Was that the thrust of the question?

 

[MHB]

Are you sure the "clock" part of the program runs during the ramp.
I'm not familiar with your auber, but other controllers I have used would, so a program that read something like 15 minutes at 50oC, 60 minutes at 65oC would do the 15 minutes at 50oC> clock stop > reach 65oC > clock start > after 60minutes > next...

Another point is that if you are adding heat too fast localised heating around the element (or other heating surface) can kill of a lot of your enzymes, this can impact on the amount of work they can do and affect yields.
It is generally considered that about 1oC/minute is the maximum safe rate of rise. That is for heat applied usually as steam in a fully jacketed stirred mash tun.

If you mashed in at say 20oC and applied enough heat to rise at about 0.5oC/minute to about 80oC, you would go through all the enzymes activity ranges slowly enough for them to do what they are going to do.
Illustrates that the enzymes don't switch on and off, they all work at ambient temperatures (slowly - it would take about two weeks to "mash" a grist at 25oC) they just get faster and faster until they reach a maximum, then start being denatured (killed).
Sort of like (out of Kunze)

Even if the clock hasn't stopped, if you are heating at 1oC/m you should still be betting lots of activity as the temperature rises.
I would have a look at your element, I suspect it might be too hot.
Mark

 

[droid]

your mash times should exclude any ramp times

as Mark says, if you're nuking your wort via the hex for fast ramp times that could be the problem, I have 4v also but ramp at 1dC per 1.5 minutes for a maxed out (volume) batch

I think Yob mentioned that at one stage he was starting his mash at cold water temp and then setting his hex to mash-out which, with his set-up would take enough time to get a good conversion

 

[philistine]

The pid won’t start the timer until the temp is at the step temp, and I think you can set the tolerance for this (I.e within 1 deg of temp).

Are you sure?
Coz I thought the same, but seem to remember checking the progress on the unit at one stage during a ramp step and saw that it had actually ticked over to the soak step and had begun the countdown before the SV had been reached.... I'll have to check again next time.


re: ramping too quickly, I am aware of that, but pretty sure that's not happening.... could be wrong though.... usually I throttle things back to make sure I don't exceed the 1c per min limit. Also, the probe is situated right at the outlet of the HEX (im using a HERM-IT like set up) so I would assume that would help mitigate any enzyme nuking....
Next brew, I'll see if I can stick a thermapen into the HEX during a ramp step and see what kind of temps the water is hitting.

As for overall efficiency losses, this was just one of my 'lines of enquiry'.
I think my main issue is due to the surface area of the grain bed vs. the wort return/sparge 'arm'. I think part of the problem is that when fly-sparging, only a small portion of the grain bed is actually being rinsed.

Cheers guys

 

[MHB]

As I said the ones I have used wont start the clock until the next target is reached, don't know about the Auber ones, it might just be a setting.

When you say throttle things back. Do you mean the heat of the element/water bath, or the flow of liquid.
If the latter, you could be making the problem worse, as the wort will be spending longer too hot. Remember that if the water bath is over 75oC you could be easily be snuffing some enzymes, especially Beta Amylase and you will miss that when its gone.
Mark

 

[philistine]

As I said the ones I have used wont start the clock until the next target is reached, don't know about the Auber ones, it might just be a setting.

When you say throttle things back. Do you mean the heat of the element/water bath, or the flow of liquid.
If the latter, you could be making the problem worse, as the wort will be spending longer too hot. Remember that if the water bath is over 75oC you could be easily be snuffing some enzymes, especially Beta Amylase and you will miss that when its gone.
Mark

By throttle back I actually mean (conversely) opening the valve on the pump outlet so that the flow increases, but the ramping slows down...

But yeah, definitely gonna check the water temp in the HEX during a ramp step next brew day

 

[Mr B]

Are you sure?
Coz I thought the same, but seem to remember checking the progress on the unit at one stage during a ramp step and saw that it had actually ticked over to the soak step and had begun the countdown before the SV had been reached.... I'll have to check again next time.

Yep, sure.

Hysteresis might be the right word. I have auber so can definitely confirm. You should get a red light when the temp is outside the parameter, assuming it is set.

Defo check the settings

 

[Nebes]

I to have this problem with efficiency and after reading this the ramp times netween temps might ne my issue. I also can confirm i have the same controller and my times dont start until my temp has been reached.