Author Topic: Pitching rate effects (experimental results)  (Read 6651 times)

Offline narvin

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Re: Pitching rate effects (experimental results)
« Reply #30 on: May 10, 2010, 07:58:15 PM »
Well said, in both posts Narvin. I'm not a ph.D or a Doctor and thank GOD I don;t wear flip flops or a loud tropical shirt but I thought the experiment was much  more approachable to the average homebrewer than some of the others I have seen, and was fairly well thought out as well.

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Re: Pitching rate effects (experimental results)
« Reply #31 on: May 10, 2010, 07:59:43 PM »
I too agree that the experiment itself is not invalid even though some of the parameters did not exactly match an actual 5 gal batch fermentation. The yeast amount could have been assed by its volume or the sediment weight.

I generally do side-by-sides where the beers are brewed 1 to 2 weeks apart. Though I'm aware that this is a problem I see these experiments as opportunities to find parameters that may be worth additional investigation or worth trying by other home brewers.

In the end it's all about the coclusions that are drawn and how much is put into the results and how strongly the conclusion is worded.

BTW, if you look at the Chris White's presentation you'll notice that in his experiments some of the flavor active components actuallty increased with pitching rate.

Kai

Offline a10t2

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Re: Pitching rate effects (experimental results)
« Reply #32 on: May 10, 2010, 08:05:23 PM »
The yeast amount could have been assed by its volume or the sediment weight.

In hindsight, that is something I wish I'd done, but my previous slurry volumes have matched up so well with the MrMalty predictions that I simply didn't feel the need. Shortsighted, I know...
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Offline akr71

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Re: Pitching rate effects (experimental results)
« Reply #33 on: May 11, 2010, 05:55:49 AM »
Thanks Sean, I thought it was a great article!

Folks, lets keep in mind that we are talking about beer.  While we all love it, the only thing that is truly important is taste, which is purely and wholly subjective (IMHO).
Andy

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Re: Pitching rate effects (experimental results)
« Reply #34 on: May 11, 2010, 07:57:12 AM »
Great discussion and debate. Great points made by Kristen. Definitely more things to consider upon further trials.
There are so many variables to consider when conducting an experiment of this nature. I am thankful to all the folks who have participated and especially Sean for conducting this experiment however flawed it may or may not be. But even more important than that it's what we have learned from this and how we will move forward as a community that counts. Keep up the great work!
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Offline mashweasel

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Re: Pitching rate effects (experimental results)
« Reply #35 on: May 11, 2010, 12:53:37 PM »
Ill just address the points as we go by briefly summarizing.

Re data access – the ability to access high end journals can get very expensive. What is not expensive, but free is the access to the abstract to any article pretty much ever written. Abstracts definitely don’t tell the entire story but will give one a very good idea of what is in the paper. Its basically a short summary of what was done and the results. Google Scholar is a good tool for the beginner.

Re controls – At the very end of the experiment you make the claim about a starter is better (we’ll get to that later). However, to have an experiment that holds water one always needs an unmanipulated control. If you wanted to test the validity of making a starter then you would need a non-starter control.

Re OG – Both do claim that you can pitch either product into <1.060 wort. However you are doing an experiment for the number of yeast to be pitched and the effects therein. In order to do this one first needs to understand that high gravity brewing is a beast of its own. This was not your experiment which needs to be addressed. Don’t get me wrong, this in and of itself is very much an experiment but not what you

Re fermenters – you are correct. Both fermenters were the same which does take out the effects that the individual fermenter geometry would play. It doesn’t, however, take into account the fermentation kinetics of that much head space and how the fermentations react/behave as such. This is something that is very easy to fix but at the same time this would not in and of itself ruin the experiment.

Re the summary – I’m not being snarky but I understand what you mean so let me explain further. You may have known what you were trying to do but in your summary and presentation it focuses on the difference between pitch rate and nothing to do with using a starter. Moreover, the starter creation is flawed as I have said before. Add to this there was no non-starter control making there no way that one can draw any solid conclusions. Let me put it a different way. What if I was trying to see if it was faster to ‘go by foot’, to ride a bike or drive a car through London in the same manner this experiment is done? I would have the car and the bike only competing. The car finishing the fastest followed by the bike shows absolutely nothing to do with how long it takes to ‘go by foot’. Does that make more sense?

Re ascertaining new knowledge from this experiment – you make a statement I hear a lot, ‘…I learned some things as a result.’ You may very well have learned things as a result but what are those things? One never really every ‘proves’ anything when doing experiments only basically disproves things. Read back through your notes, see what you can find. Go back over my points and see what you can improve. One of the most important things that I haven’t touched on are the number of repeats you did with this experiments. Meaning how many of each did you do in duplicate, triplicate, etc. The reason we do this is b/c single experiments are inherently flawed. Even if you kept everything the same it would have been better to do 2 sets of 3 one gallon fermenters.

Re the ‘its only beer’ theory – If people put the time and energy into doing an experiment, they, just like me, don’t want to be wasting their time. On top of that people brewing beer don’t want to be wasting their time. I very much understand that a lot of this technical knowledge hasn’t been seen by the average home brewer. Any sort of experiment people love. However one needs to take everything with a grain of salt. Does it make sense? Was it carried out well? Etc etc. This may be only beer but don’t tell me that if some dude did an experiment saying that olive oil should be put into a beer and then there is really no need for oxygen that if the beer then went south and wasn’t shelf stable people wouldn’t be pissed! BTW – this last one happened. Research New Belgium olive oil. A dude wrote his Masters on it if I’m not mistaken.

Please keep up this conversation as it helps everyone out.
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Kristen England, Ph.D.
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Re: Pitching rate effects (experimental results)
« Reply #36 on: May 11, 2010, 01:33:21 PM »
Kristen,

You are a man that speaks with profound confidence on this subject. You get my vote to set up the next experiment on Pitching rate effects. I still have to give Sean credit for his work. Whether he proved or disproved the theory, he did a great job.

I see you may be in the running for this years Ninkasi. Good Luck with that!
Ron Price

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Re: Pitching rate effects (experimental results)
« Reply #37 on: May 11, 2010, 01:47:44 PM »
Ill just address the points as we go by briefly summarizing.

Re data access – the ability to access high end journals can get very expensive. .... people wouldn’t be pissed! BTW – this last one happened. Research New Belgium olive oil. A dude wrote his Masters on it if I’m not mistaken.

Please keep up this conversation as it helps everyone out.


Kinda disappointed you didn't address the flip flop, Hawaiian shirt conundrum....
Keith Y.
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Offline narvin

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Re: Pitching rate effects (experimental results)
« Reply #38 on: May 11, 2010, 02:00:07 PM »
I agree that if you're doing an experiment, you should do it properly, or it's not worth doing.  But I don't think everything has to be in commercial / academic terms -- no one here is trying to write a paper published in a journal.  What's the point of talking about cell count if most homebrewers don't have a hemacytometer?  Home-friendly units like starter size (as long as you can replicate the conditions -- stir plate, 1.040 OG, pitched one tube of White Labs, etc) are "good enough" in the sense that the pitching rate will be within a range that provides similar fermentations to other homebrewers.  Of course you can't pitch some old slurry from the back of your fridge and expect the same results, but there's enough info on making starters that homebrewers should know this.

Is brewing a science?  Is it engineering?  Is it art?  It's a little of everything, but in the end, what matters is that the beer tastes good, not that it has sound theoretical underpinnings.  A beer isn't going to become invalid like a public key encryption algorithm if the prior research turns out to be wrong.  I don't see any reason why science is a necessity to make a good beer that you can brag about and compare to the best commercial beers.  What about the cheese maker who knows nothing of the enzymes and molds that make the cheese, but knows exactly what to do and when to do it based on generations of trial and error?  Science can tell us why things are happening and help us to improve faster, and help to create consistency in large industrial settings, but it's not the end all for making great beer.
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Re: Pitching rate effects (experimental results)
« Reply #39 on: May 11, 2010, 02:26:27 PM »
Re the summary – I’m not being snarky but I understand what you mean so let me explain further. You may have known what you were trying to do but in your summary and presentation it focuses on the difference between pitch rate and nothing to do with using a starter.

I see, your concern is that I'm making a statement about starters when what was actually tested was the pitching rate associated with using a starter or not. You're absolutely right about that, and it's something I actually addressed briefly on the episode of Basic Brewing that will air tomorrow.

And by the way, I meant that I was being snarky (when I wrote that), not you.

One never really every ‘proves’ anything when doing experiments only basically disproves things.

I certainly wouldn't claim that this experiment proves or disproves anything - the data can only support or fail to support a hypothesis. There's no such thing as absolute proof. That fundamental fact doesn't validate or invalidate the data though.

One of the most important things that I haven’t touched on are the number of repeats you did with this experiments. Meaning how many of each did you do in duplicate, triplicate, etc. The reason we do this is b/c single experiments are inherently flawed. Even if you kept everything the same it would have been better to do 2 sets of 3 one gallon fermenters.

I do understand the importance of repeatability, but the one gallon fermenter idea seems a little impractical. If different tasters received beers from different fermenters, it would add an uncontrolled variable. And if each taster received beers from all three fermenters, it would demonstrate repeatability, but cut the sample size by a third.
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Offline akr71

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Re: Pitching rate effects (experimental results)
« Reply #40 on: May 11, 2010, 02:41:35 PM »
... Please keep up this conversation as it helps everyone out.
Don't get me wrong, mashweasel, I thoroughly enjoyed reading your critique of Sean's experiment.  I'm no scientist, but the idea of a repeatable procedure & peer review is not new to me, so your insight was quite enlightening.  I also really enjoyed reading Sean's article.

Now, the 'only beer' thing I said...
Folks, lets keep in mind that we are talking about beer.  While we all love it, the only thing that is truly important is taste, which is purely and wholly subjective (IMHO).
All I was really trying to say was that we are all passionate about beer (or else we wouldn't engage in this hobby).  If Sean took the time to round up some tasters, gather their subjective opinions and write it up for us to enjoy, lets take it at face value - they are subjective opinions about beer.  Reading peer reviewed articles is great, but nothing beats the empirical evidence gathered by your own senses from a couple of frosty pints!
Andy

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Offline dean

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Re: Pitching rate effects (experimental results)
« Reply #41 on: May 12, 2010, 08:58:47 AM »
Kristen,

You are a man that speaks with profound confidence on this subject. You get my vote to set up the next experiment on Pitching rate effects. I still have to give Sean credit for his work. Whether he proved or disproved the theory, he did a great job.



Gotta give credit where credit is due, most homebrewers rely on other homebrewers for many experiments and very few of us are able to maintain a lab quality, controlled experiment.  I'm into it for the beer, yeh some are better than others but if I can brew a decent beer that other people like... why tell them I might have sneezed over the brew kettle?   :D  ;) 

I like being able to read a report without having to take a class to understand what a cyclotron or some other gadget is, don't get me wrong I do appreciate those experiments... I just wish those experimenters (scientists) wrote their report like they were addressing ME rather than a group of professional scientists in such a manner that it seems they are seeking a nobel prize etc.  We're "home"- brewers that like to dabble just enough to hopefully make decent beer on a regular basis for the most-part.   :D

Kris, yeh, I like reading your posts on what you've found or done too... but you're a bit wordy sometimes and I start drifting... not your fault but mine, I'm getting old and like to cut to the chase more now.

Sean... great job imo.   8)




Offline glitterbug

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Re: Pitching rate effects (experimental results)
« Reply #42 on: May 12, 2010, 10:35:05 AM »
I like being able to read a report without having to take a class to understand what a cyclotron or some other gadget is, don't get me wrong I do appreciate those experiments... I just wish those experimenters (scientists) wrote their report like they were addressing ME rather than a group of professional scientists in such a manner that it seems they are seeking a nobel prize etc. 

You are not the intended audience for those types of experiments and reports and asking scientists to cater to your intellectual capacity is a little silly  :)
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Re: Pitching rate effects (experimental results)
« Reply #43 on: May 12, 2010, 11:05:25 AM »
I just wish those experimenters (scientists) wrote their report like they were addressing ME rather than a group of professional scientists in such a manner that it seems they are seeking a nobel prize etc.

I don't think that the write-up of the experiments should be simplified as much as possible in order to make them more understandable. Most of these write-ups are simply for the sake of documenting what was done which allows peer-review. This way the experimenter down't have to worry about the audicence.

However, I do agree that it is helpful to present conclusions drawn from the experiment in simple terms since this is what most other brewers are looking for.

Kai

Offline dean

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Re: Pitching rate effects (experimental results)
« Reply #44 on: May 12, 2010, 01:41:19 PM »
Wow, I thought the major breweries had their own scientists and reports.  I guess I just thought discussing pitching rates for 5 or 10 gallon batches in an in-home setting was more of a home brewers issue.

Glitterbug, you're full of yourself aren't ya.  I believe you will teach one day.   ;)