experiment – Alexander Miles

Fungiculture: Oyster Mushrooms

It has been a while since I’ve been able to post an actual update, having gotten a job, moved, and settled in during the interim. Having met with some small success growing a few basil plants indoors, I decided to branch out into mycoculture, or mushroom growing, as the requirements are a bit stricter, supplying a bit of an engineering challenge in getting it right. While it’s totally true that, given my choice of oyster mushrooms (pleurotus ostreatus) for my first attempt, I could have just as well used a plastic bag and a spray bottle, however that would not have scratched my data-gathering/total automation itch. Now let us get to the admittedly over-kill list of parts I ended up using.

List of bits
- Aquarium
- Hygrotherm humidity controller
- Humidifier
- Data logger (not necessary, but fun)
- Mycelium brick

During this first week-long time lapse we kept the aquarium light on continuously to provide consistent illumination for the camera, and realized that consistent (and blue) light strongly inhibits mushroom growth, which turns out to be a well-established fact so for a week we saw very little happen aside from a moderate whitening of the surface of the mycelium-log. After a week of watching, we folded and decided to shut it down for the evening and go to bed. Of course, finally given a break from the light, mushrooms immediately appeared over night, so we excitedly resumed the time-lapse capture the following morning, resulting in the second video.

First week, under constant illumination (not much change)

Second week, without night illumination

By the end of that week we had a full flush of mushrooms to harvest, as shown in the photos below. I probably waited about a half-day too long, given that the cap-edges were just slightly beginning to droop. After cutting them from the base with a kitchen knife, the heights and cap-widths were measured for later comparison, and the rinsed mushrooms were stir-fried with green onion and garlic! They were pretty tasty! Given that I don’t usually eat mushrooms I was surprised by how much I liked them, but the inevitable bias towards something I made myself can only help. I also managed to log the conditions over the first 12 days (missing the last bit of the fruiting stage before harvesting); those data are shown below. The placement of the two sensors probably makes up for the fact that the controller was reporting ~70% RH while the logger reported values around ~60%, but there are some relatively easy calibration tests that can be done.

Plots of the temperature and humidity as a function of time over the first 12 days.Without further delay, I should show off the fruits (kinda) of my labor, the mushrooms!

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Rather than use this as a one-off experiment, I’ve already got the tank back under humidity control and monitoring, the first beginnings of a new flush of mushrooms are just now showing themselves. Moving forward I might try to simplify the setup, as I’ve read that environmental monitoring and power control are super-easy with cheap single-board computers (e.g. raspberry pi). It’s only coincidence that I’ve been playing with those lately for other project, just 4 years behind the curve!

Cooking: Barbecue Sauce Experiment, First Four

I've always had a soft spot for good barbecue, and I include pretty much any meat cooked low and slow for long times when I say that. A key part of BBQ for me is the sauce, and there are many restaurants that do it really really well. In Tucson alone we have Mr. K's (easily the favorite, but quite a drive) and Brushfire BBQ, both of which have amazing sauce. I've been eating a lot of chicken over the past few years, as it's cheap, full of protein, and easy to make delicious. BBQ sauce usually finds its way into either the marinade or goes on top right before I eat it, but it's always been the store-bought stuff. After seeing fantastic results by dousing my chicken in some leftover sauce from Brushfire, it occurred to me that I should try to make my own rather than buy it pre-made. I looked around the internet for recipes and found that not only were the majority of the ingredients were already in my kitchen from making beef jerky, but every recipe (with minor variations) used the same core ingredients. I selected 11 different recipes and gathered all the ingredients necessary. For the preparation, every recipe had some variation on "mix the ingredients, bring to a boil, simmer for a while". To minimize the variance I'm applying the same preparation procedure to each run, whisk together everything on the list, bring to a boil, then simmer over low heat for 45 minutes. I'll be recording my commentary on each batch here, along with anyone I can conscript into giving their thoughts.

Ideally, once a good number of established recipes are tested, I'll have enough information to begin manually probing the phase space. While reading I've come across variations that merit investigation, such as using coffee in place of water, or making an entirely mustard-based sauce. Whiskey and honey variations are also on the list. From all this I hope to arrive at a recipe that I like the most, though I wouldn't be disappointed to accidentally replicate Mr. K's sauce.

Batch #1: The first recipe I tried had the slightly over-the-top name, "The Best Homemade BBQ Sauce Ever". Essentially just ketchup, apple cider vinegar, water, brown sugar (I used dark, other recipes call specifically for light), worcestershire sauce and spices. The first tastes, albeit on its own and with a tortilla chip, yielded lukewarm responses: "Very mild. Doesn't really stand out. More spices would improve it." and "Yep, that's barbecue sauce.". Over scrambled eggs it was totally usable, with just the slightest kick of heat, lots of sweetness and vinegar forming the base of the flavor. Several chicken breasts were marinated in the sauce, cooked at 350 F for 30 minutes and served with the sauce on top. On chicken (first day): It's got a good amount of sweetness, but the rest of the flavor is dominated by vinegar. On the second day I was looking forward to it, tasty, just not life-changing.

Batch #2: For the second trial I decided to go as far afield as I could. I selected this recipe, entitled simply "Absolutely Awesome BBQ Sauce". It drops the cider vinegar entirely and adds a comic amount of hot pepper sauce (I used Tabasco), which does indeed contain plenty of vinegar. In addition is uses rum (dark, I'm guessing), soy sauce, and crushed cloves of garlic, which make it rather unique among the ones I collected. My first impression while cooking it was that it smelled substantially more salty and spicy, and that definitely comes through in the taste. I first tried it over eggs. Quite spicy, especially compared to #1. Definitely more flavors running around, which gives it some depth, but the spiciness needs to come down for it to be competitive for most people. In future iterations I imagine I'll bring the Tabasco down by half and substitute additional ketchup, water, or rum. This one also came out surprisingly thin, consistency-wise.

Batch #3: The third recipe I tried involves yellow mustard, which was a first. Outside of that it held fast to the basic building blocks of ketchup, brown sugar, cider vinegar, and a few spices. It definitely didn't have the super-spicey problem of #2. Just like the others this was tried on chicken breasts and eggs. Strong tangy vinegar and mustard flavor at the fore, with just a hint of heat. My first thought is that this could use black pepper for a little more kick. The second taster confirmed that it was his favorite so far.

Batch #4: The fourth recipe, marketing itself as Big Daddy's Carolina BBQ sauce, was a second vinegar-and-mustard based attempt. In addition, it required an extra ingredient that I don't usually keep on hand: ground white pepper. I was able to pick up a few ounces at the local spice shop for about $3. The preparation also had a minor alteration, a handful of the unique ingredients had to be added in a second heating step, namely the butter, soy sauce, and liquid smoke. I did deviate from the published recipe by reducing the liquid smoke to 1 tsp from 1 tbsp. My initial reactions while preparing this included "Wow, that's really a lot of chili powder", and "this is a lot thinner than the other sauces". There was less apparent mustard taste compared to #3, and a slow building heat as opposed to the instantaneous heat of #2.

Results of Coffee Experiments

I wanted to follow up on the previous post before the end of the month, so I went ahead and ran the extractions yesterday evening. The results were just about what one would expect, with one difference: agitation did not have an appreciable effect on caffeine extraction. An additional concern was the efficiency of the extraction, so I added an additional sample to as a pseudo-standard, namely standard brewed coffee from the office Mr.Coffee machine. With this I was able to determine that the extraction was roughly 33% complete, but there is some margin of error there.

	24 hour with agitation (#1)	24 hour still (#2)	Office coffee (#3)	Diet Coke*
Crude Caffeine Isolated (mg)	14.30	16.74	3.10	-
Total Caffeine (mg/cup)	451	550	100	29

* Literature value via the Mayo Clinic. Chosen due to how frequently my friends consume it.

The second interesting result was simply how much stronger the toddy (24 hour cold brew) was compared to standard hot drip coffee and soda; more than 5 times as much caffeine as the office brew, and 19 times as much as a cup of diet coke. To be fair, people typically drink coffee in smaller volumes. I worry that these numbers may be too high, as I'm not sure what share of the measured mass is impurities. If the numbers are close, that'd solve the riddle of why I've been so susceptible to caffeine headaches when I miss my morning coffee, I used to drink almost a cup of toddy a day.

I want to emphasize that I am not a chemist, I've not been trained as such, and having a background in materials science is not "pretty much the same thing". As such the experimental procedure was just as interesting to me as the result. I will not reproduce all the details here, as there are many many write-ups for this exact extraction out there. Several of the more frustrating bits I will, however, elaborate on. Namely the problem of emulsions. If you've ever seen oil and water, you know they separate into layers, but if you shake it enough you'll get a layer made of bubbles of one in the other that persists; That's the emulsion. Through the three trials I tried a number of methods for getting rid of the emulsion after agitating the coffee with dichloromethane.

Cleanly separated layers of coffee and dicholormethane. — Cleanly separated layers of coffee and dichloromethane before agitation.

As I couldn't get my hands on a sepratory funnel, I ended up using a column with a loose glass top stopper. This prevented me from mixing the liquids by simply inverting it slowly, so instead I swirled it such that the liquid at the top got pulled to the bottom and vice versa. This produced varying levels of emulsion across the three samples.

I tried stirring with a glass rod, and that helped some. A write up I found online suggested sonicating, which only served to worsen the problem. Waiting produced the most consistent improvement. The clear answer was to decant the whole mess and centrifuge it, but due to time constraints I opted to stop decanting right at the emulsion's edge (hence the 33% extraction, which should have been much better). The final result contained at least some contaminants, as caffeine ought to be a white solid and what was yielded was yellow to brownish red.

The take-away from this experiment is two-fold: agitation has no significant effect on the extraction of cold-brewed coffee, and cold-brewed coffee is ridiculously strong even given a large margin of error. Were I to repeat these experiments again I would filter after the introducing the calcium carbonate rather than allowing it to settle and pipetting off the top, and I would agitate in a sealed container (venting occasionally) and centrifuge the result to sidestep the whole emulsion issue. I've read that a sublimation purification can also reduce the apparent color, but some of the results I've seen are not promising.

First Coffee Experiments

I've been in the habit of making weekly batches of 24 hour cold brewed coffee. Taking the name literally, this meant tossing one cup of medium grind into my french press, topping it up with water, stirring a bit, and tossing it in the fridge until the next morning. I'd noticed that every time it came time to take the coffee out, a semi-solid puck of coffee ground has floated to the top. An independent island where no extraction could occur. I decided to make an experiment of it, seeing what happens when the grounds are constantly agitated and this agglomeration wasn't allowed to happen.

The first step was figuring out how I would manage to agitate it. Stir plates are relatively expensive, but seemed like the right way to go about it. I found a few tutorials on putting together one for cheap using a computer fan, some super magnets, glue and a power supply. Save for the magnets which I was able to get for about $7 from amazon, and the fan (which was donated by an awesome friend) I had everything on hand. It came together in just about an hour, and is still without a housing. Still, it does the job.

For the first real experiment I kept constant everything I could (being time, water/coffee ratio), though the temperature was higher than previously as I haven't found a good way to squirrel the whole setup into my fridge. After the full 24 hours of agitation (making plenty of noise) the resultant liquid was what could best be described as "muddy".

After being french-pressed to remove the larger particles, the resulting liquid passed freely through a coffee filter, but rapidly clogged a #1 United standard filter paper (11 micron pore size). The solid left behind had the consistency of clay, indicating that the agitation may well have been crushing the grounds into fine dust. This was further suggested by the fact that even in the flask I was filtering into, a sedimentation became apparent. I decided to allow the liquid to settle (in the fridge) for four hours before carefully removing all but the bottom-most liquid. Eight hours later there was no sediment apparent, so I decided that I'd gotten out what was going to settle out.

Shortly here I should be able to isolate the caffeine from this batch as well as a similar batch prepared under identical conditions excepting agitation, and will toss my results up then.