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Topics - lupulus

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General Homebrew Discussion / Webinar on Hot Side Oxidation
« on: September 05, 2017, 09:44:11 PM »
Fellow brewers: As part of the Zymurgy Live series, I will be giving a presentation on Hot Side Oxidation.  Looking forward to your participation. Cheers,

https://www.homebrewersassociation.org/events/hot-side-oxidation-fact-or-fiction/

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General Homebrew Discussion / Interpretation of Beer Experiment Results
« on: August 23, 2017, 04:36:17 PM »
There is an abundance of literature on interpretation of experimental results but it seems that many homebrewers continue to ignore this literature and misinterpret experimental results.

EXAMPLES OF MISINTERPRETATION
As examples of this misinterpretation that motivated me to write this topic:
- Stan Hyeronimus recent article on First Wort Hopping
- A friend commenting on a post that there is no difference between step mashing and infusion mashing (and sending a link to the Brulosophy experiment on the subject)

I will do my best to avoid scientific jargon in my discussion below...

POSITIVE RESULTS
A positive result is when the investigator reports a statistically significant difference (commonly 95% or higher probability) between the treatments.
Statistical outcome: under the experimental conditions proposed (very important caveat) it is highly likely the treatments are different.
Practically it means that it is likely that (if you reproduce the design and use the same beer style) your beer will be different with one vs. the other treatment.

NEGATIVE / NULL RESULTS
A negative or null result is when the investigator reports that there is NO statistically significant difference (commonly 95% or higher probability) between the treatments.
Statistical outcome: None. No statistical conclusions can be drawn.
Practically it means that you should ignore the results until further information is collected.

REASONS FOR NEGATIVE / NULL RESULTS
-   A combination of the below
-   The treatment studied has no or minimal effect on beer (this is what most people think it means)
-   The sample size chosen to test the beers was too small, and if larger, they would have detected a difference (insufficient power in stats jargon)
-   Beer style tested not the correct style for the experiment
-   Experimental design had one or more imperfections. This includes not only the brewing ingredients and process itself but also the testing conditions.
-   Experimental design was not correctly executed. (do not take offense, all investigators must consider this possibility)
-   Beer quality not very good, confounding the experimental variable (do not take offense, all investigators must consider this possibility) (this is related to both experimental design and its execution).
-   Random error (aka chance)
-   Others

WRONG INTERPRETATION OF NEGATIVE/ NULL RESULTS
Many brewers keep interpreting null results as “The treatment studied has no or minimal effect on beer”. This is not correct. Any of the listed reasons and at various “weights” could lead to negative/ null results.

SHOULD NEGATIVE/ NULL RESULTS BE PUBLISHED
The answer is almost always YES. The only caveat is that the experimental design must be correctly executed. If the investigator aimed for two 1.050 OG worts, and one of the worts ended at 1.040 unexpectedly, the investigator must repeat the experiment. If it happens twice or more times, then the investigator may be in the presence of an unexpected finding that warrants further study.

CAN SIMILARITY / EQUIVALENCY BE STATISTICALLY TESTED?
The answer is theoretically yes, but the experiment design would be much more complex, time consuming and costly. Because even if proven statistically, results would only apply to the experimental design tested, there is no valid rationale to design equivalency experiments.  Experimental designs whose statistical goal is to reject the null hypothesis are much simpler.

SUGGESTIONS FOR IMPROVEMENT
On experimental design, the best suggestion for beer investigators is to perform a thorough literature search. It will not improve our understanding of a question, to design experiments without knowing previous experimental designs, their successes and flaws; it will just create confusion.
On interpretation of experiments, please refer to the REASONS FOR NEGATIVE / NULL RESULTS. Do not over interpret results.
Cheers,




3
Fellow homebrewers,
I started this thread not to promote any candidates but to help coordinate the raising of issues/ topics/ actions that can make our hobby better.

You may have seen by now that for good or bad, I am very science-oriented. Cannot help it :-)

What can help me personally and I am sure it would help many other homebrewers is for the GC to facilitate our access to research publications on brewing.
Ideally of course, would be free access to a given journal for AHA members, but more realistically, I think a student membership for AHA members (that are not pro brewers) can be negotiated with most journals.
Examples are :
MBAA technical quarterly
Brauwelt international

There you go.. What do you fellow homebrewers wish to see done that is not part of the commitments of current candidates?

4
I wish to share a thought with the forum after reading for the nth time that somebody interprets the researchers not finding a significant difference as the treatments being the same, or that it makes no difference whether I do X vs if I do Y, because this experiment found no difference.
It seems important then to state that failing to find a significant difference can be related to many other factors, for example sample size not being large enough, confounding variables having a larger weight vs the experimental variable, etc.
In other words, failing to prove that there is a 95% probability that treatments are different, does NOT mean that there is a 95% probability that treatments are similar, or even 50%, or any probability. We just do not know...



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General Homebrew Discussion / International presence at HombrewCon
« on: January 11, 2017, 05:23:05 PM »
Having spoken about this topic with Gary Glass at HomebrewCon, then with a board member 2 month ago, and seeing no traction for the idea, I would like to put it out there to see if the idea gets some traction:

- My proposal was for HomebrewCon to "officially" invite homebrewers from other countries to join us at HomebrewCon. Every year, a new country will get the "official" invite, which can be something along the lines of:
- if at least 6 but no more than 10 homebrewers from your country attend HomebrewCon, commit to attend club night as a club, and bring at minimum 20 liters of homebrew for tasting, HomebrewCon will subsidize your trip by giving you a ~80% ? discount in the conference cost.
The discount can vary depending on the country (the longer the trip, the higher the discount).
Homebrew groups from other countries are encouraged to attend as "Clubs" but only one country will be invited each year.
- The details can be changed/ adapted as the board deems fit but I am sure you get the idea.

That's it. Cheers,

6
I went for a run today, and as usual I played one of the well-known podcasts, Dr Homebrew (Episode #78). The first beer was a Spruce tips IPA, and at the end of the discussion, the judges indicated that one of the things to correct was the haze of the beer. The brewer responded that the beer was not hazy, and that to mimic shipment shake his bottle every day during shipment time then when the package arrived, put it in the fridge, and that he was drinking along with the judges and the beer was clear. To this, JP admitted that the beer was probably shaken during the drive to the studio for the program. No apology, no "we should do better from now on", nothing. Many, many times in the same show judges noted haziness in the evaluated beers, but because the brewers did not do the same process as the spruce tip guy, Dr Homebrew got away with blaming the shipper.
Honestly, I was appalled that the beer was not at the judging location for at least a few days to avoid this problem and give the beer a proper evaluation.
Haze changes the beer quite a bit, sometimes for the better (weissbier, wit), sometimes for the worse, specially if the haze is not hops (eg New England IPA).
So, my question to the forum is whether there is in your view an implicit obligation that when you send a beer to be judged, to a podcast in this case but it can be a competition, the Brewing Network (or Competition Organizers) should do their best to ensure the beer is stewarded appropriately.
What say you...

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General Homebrew Discussion / Dry hopping and perceived sweetness
« on: May 27, 2015, 03:54:04 PM »
Hi all,
Sorry to be perceived as beating as dead horse... I brew very dry IPAs and DIPAs. I have Pliny (Elder) clones finishing at 1.008 to 1.009, and I have always perceived a touch of sweetness that I do not perceive in other beers. Because Pliny calls for a Caramel malt (using Caraamber because it is what I get in Munich), I forced myself to keep my mouth shut about this sensation, thinking that this perceived sweetness should be from the Caraamber. And before, you say "oxidation", I bottle condition (or keg condition) IPAs and the only transfer I do, is before fermentation is completely done, so any oxygen during the transfer is theoretically absorbed by the yeast.
So, after a visit to Austin, Texas, I decided to clone Noble King, a dry hopped sour, bought a bottle, grew the culture, Fermented it for two weeks to 1.003, and dry hopped with 75g of Mittelfrüh and 75g of Mandarina Bavaria (whole hops) for a 21 liter volume. (I tasted the beer before dry-hopping and noted no sweetness at all.). Finished dry hopping and keg most of the beer with sugar at 5g/L and left it conditioning for 3 months at about 20 Celsius (68F). Chilled the keg two days ago, tapped today, and tasted the beer. It is very good, lemony sour, bretty aromas, dry hop spicy flavors, and SWEETNESS. The sweetness cannot be described as malty, it is very simple, like splenda/ stevia (no sugar coating). So, I checked for gravity to ensure the sugar added for carbonation was consumed, and the beer (degassed) was at 1.002. The important point to keep in mind, is that we are talking about a truckload of dry-hops, so please only comment if you have experience with the "truckload model". So, as Sherlock use to say, "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth."
Now your turn to shoot me down :-)

8
Dear homebrewers:
My first question/ post. I really look for this answer so please be forgiving if it is given somewhere else...
(I also sent this question to Kai but thought it may be interesting to see whether others asked themselves the same question)

I moved to Munich more than two years ago and as I brew mainly pale beers, I control the pH using acids, either lactic or citric, and a pH meter (sorry Reinheitsgebot).
The water profile in Munich is such that pre-boiling the water (before mashing) would lead to precipitation of most calcium (and magnesium?) and bicarbonate ions as calcium (and magnesium?) carbonate. Many brewers in Munich including many pros boil their water and then separate the water from the precipitate.
At the moment, I pre-boil water and separate it from the calcium carbonate precipitate. However, as I use the brew-in-a-bag method, to separate the calcium carbonate it would be more convenient for me to boil the water, have it cool down and have calcium carbonate precipitate, in the same kettle do the mashing then take the grains out boil the wort, cool it down (immersion chiller) and transfer all but the bottom residue to the fermenter. I reason that the calcium carbonate may continue to be in the bottom of the kettle throughout this process and is separated from the fermentable wort as calcium carbonate will stay with the trub in the bottom of the kettle.
In other words, my question is: Why german brewers separate the boiled water from the calcium carbonate precipitate, if you can leave the precipitate in the bottom (in brew in a bag) or leave it as a salt in a regular mash that eventually will settle as part of the trub after the normal boiling and cooling? Is it that the acidity of the mash and/ or boil will actually dissociate the calcium carbonate into ions and at least part of these ions will end up in the final beer, making it more "chalky" that it would be otherwise.

Thanks for reading and I would appreciate any comments  :)




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