Before the hiatus, I made an attempt at creating a Continuous Fluid Density Sensor. Here are the primary components: Two dip tubes in the fermenter MPXV7002DP differential pressure sensor ADS1115 16-bit analog to digital converter Generic, chrome plated brass, 2.5 mm hose barb to M3 adapters and 2.5 mm pneumatic hose Generic 12V aquarium diaphragm pump (model no longer listed on eBay) Plumbing The first step was to install new dip tubes into the fermenter. These are just two tubes in the tank that terminate with their openings directed downward. They are connected to cam-lock adapters on the outside of the tank for attachment to hoses. I also wanted the portions of pipe inside the fermenter to have as few recesses as possible to limit contamination by undesirable microbes. I soldered the NPT stainless fittings using acidic flux (I used Stay-Clean). The 1/4″ stainless tubing connects through a compression fitting. These leaves less room for leaks and microbes. Now that we have dip tubes between which to measure the pressure difference, the first step in design is to calculate the expected difference in the pressure at the tip of each tube. The difference in their heights is approximately 15 cm. The conversion between Pascals and centimeters of water is , so the differential pressure between the two tubes due to a column of water is: The original gravity for a generic pale ale is approximately 1.05, so the differential pressure at the beginning of fermentation would be: The final gravity for a generic pale is about 1.011, so the differential pressure at the end of fermentation would be And finally, the change in the differential pressure is . The dip tubes need to be connected to a differential pressure sensor. The pressure sensors in the price range for this application connect via 2.5 mm pneumatic hose, but there are no adapters between pipe fittings (what I use in my brewery) and this diameter hose. So, I made adapters by taking a short length of 1/2″ NPT copper pipe and soldering a brass hose barb into it. The plating on the brass interfered with the soldering, so grinding down the threads on the barb before soldering was necessary. Diaphragm Pumps Lastly, the dip tubes will have a tendency to fill with fluid. Measuring the differential pressure will require a means to push the fluid out and fill the tube completely with gas. That’s accomplished with two diaphragm pumps. These simply take gas from the top of the fermentor and push it through the tubing leading to the dip tubes. MPXV7002DP This device is a differential pressure sensor. It operates at 5V and outputs an analog voltage between 0.5V and 4.5V that is proportional to the pressure detected by the device. Specifications dictate that this device detects a -2.0 kPa to 2.0 kPa range at 2.5% average and 6.25% maximum error. The first question is whether this is a significant error. At a range of 4000 Pa, the average error is 100
My first brew day since the Core exam was spent making a beer with my buddy Cody. We took a shot at a clone of one of his favorite beers, St. Arnold’s Santos. They call this a Dark Kölsch and admit that this is very much a contradiction. Breaking brewing rules sounds like good fun to me. I couldn’t find any recipes for this clone, so I used Brew Target and the ingredient list from St. Arnold to come up with something. Recipe Mashed at 153 for one hour: 9 lb US 2-row pale 9 lb US pilsner 2 lb German Munich 1 lb Black Patent Hops: 1.5 oz Hallertau, 60 min 1.0 oz Hallertau, 30 min 1.0 oz Hallertau, 15 min 0.5 oz Hallertau, 5 min One hour boil, fermented at 16 degrees C (or as close as I can get) with Wyeast 2565. OG: 1.050 FG: 1.01 ABV: 5% A New Tool This was the first batch for which I used a new tool that I built, which is just a small stainless pot modified with a thermometer and a dip tube that I’ll use to make yeast starters. I attached a small aquarium air compressor to the dip tube to agitate and oxygenate the wort in an effort to improve the yeast health and number. I was a little more structured with my yeast starter this time, which was made with 2 liters water, 4 cups dry malt extract, and a half-cup of dead yeast. I should have also been able to use the compressor to force the yeast out of the bottom into the fermentor by attaching it to the top port I added, but a little of the dried medium created a small leak in the silicone gasket sealing the top of the pot. Maybe next time. Brew Day Cody and his wife Stephanie joined us for this brew day, and it was a great time full of laughter, delicious beer, and great food. Trang made double squid ink pasta with crab, and Cody supplied lots of Santos. Brewing went as smoothly as my brew days ever go, and I was a little rusty. We did multiple sparges and almost nailed the target OG of 1.051. It’s taken the temperature controller a couple of days to get the temperature down to the target of 16 C due to the warm weather, but it’s holding nicely. Here’s a screenshot from my JavaFX application that interacts with my Arduino-based temperature controller. Will this beer taste just like Santos? Probably not. Will it be as awful as the beer I brewed for Jeff and Adam? Impossible (sorry, guys!). I think it’ll be tasty, and I hope to have some carbonated by the time my dad visits late this month. Cheers!
I’m still a slave to the books, but I occasionally decompress with a little eBay browsing. I’m accruing material for projects I’ve got planned for my glorious post Core Exam days, but I couldn’t resist giving one cool little tool a test drive. A common need in making brewing hardware is a hole in sheet metal for a valve or instrument. You can buy a pot with the parts already installed, but you can also do it yourself. So far, I’ve just been using a step drill bit. This certainly gets the job done, but it takes forever, leaves a lot of metallic swarf that’s hard to clean, and leaves a jagged edge that takes a lot of sanding. The hole punch is a better tool. This is a bolt with a threaded punch and die that cuts a clean, perfectly sized hole. The Greenlee brand is popular but expensive; the 7/8″ punch required to make a hole big enough for a 1/2″ NPT bulkhead costs over $80! I lucked out and found a used one for $13 on eBay, so I pounced. Drill a 7/16″ hole for the bolt, place the hole punch, and tighten down until the punch passes into the die. The punch is definitely the way to go. This hole is in my hot liquor tank for a thermowell. A little Teflon tape and silicone sealant goes on the outer threads, which are 1/2″ NPT. A 13/16″ ID x 1 1/16″ OD silicone o-ring goes into a 1/2″ NPT locknut and will secure the thermowell on the inside, making it water tight. There we are. A newly mounted thermowell. A thermometer with 1/4″ threads to match the thermowell goes inside. The nice thing about the thermowell is that I can later install a digital thermometer when I want to automate the hot liquor tank. All that’s left is to pressure test it. No leaks! Now I want to find a 1-1/4″ hole punch to put electric heating elements in my pots, but that will have to wait. Back to the books. Just a few more weeks until the big test.
A couple of friends and I have been planning a brew day, and we’ve been looking forward to it for months. It was tough to wait this long between brew sessions, but it was well worth it. In building the recipe, we decided to be ambitious and attempt a clone of pFriem’s Dark Strong Ale. As far as I’m concerned, there’s no style superior to the Belgian Dark Strong. Jeff found pFriem’s ingredient list, but neither of us could find any posts about an attempted clone. A little tinkering with BrewTarget yielded a first draft recipe. While the style demands little hops, Adam nudged the hop additions a little higher than what BrewTarget initially suggested would put our bitterness in range for the style. Fine by me! Finally, a great Belgian style deserves a great Belgian yeast, so we went with Wyeast 3787, their Westmalle strain. This yeast is not only used by the Westmalle Abbey but the Westvleteren Abbey as well. As always, the practical substitutions had to be made at the brew store. Here’s the full recipe: Mash 23 lb 2-row pale 1 lb Carafa II 2 lb Caramunich Mash at 162 for 75 min Boil 5 lb homemade Dark Candi Sugar, 60 min 1 oz Fuggle, 60 min 1 oz Norther Brewer, 30 min 1 oz Tettnanger, 10 min Fermentation 800 ml starter Wyeast 3787, fermented at 23.3 degc OG 1.103 SG to be measured More than anything, the available food and libations stood out this brew day. Between the three of us, we built quite a menu of beers to quaff, and we nearly finished them all. Furthermore, not only did Trang’s mom watch My Lan for the day, she made her incredible chicken wings. All grain brew days are long, but we were neither hungry nor sober! I’ve only made a few small changes since the last brew day. First, I modified a pressure cooker to supply pressurized steam for sanitizing my heat exchanger. I just drilled a hole in the top for a cam lock fitting. When it’s time to sanituze, I put the pressure cooker on a hot plate and attach it to my exchanger. Voila, low pressure steam does the sanitizing for me. I previously had to boil water and pump it through, so this is obviously much faster and doesn’t tie up my brew pump for half an hour. Second, I added a manifold to my rig. This allows me to divert the recirculating wort to the brew kettle as well as direct water from the hot liquor tank to the mash tun without any fumbling around with hoses. The pump inlet piping still needs some work. Lastly, I built a stand for my hot liquor tank so it can drain into the mash tun by gravity. We had some trouble with the flow getting hung up at a high point in the flow path, so I’ll have to pay it more thought. The improvements were small but made it my
Merry Christmas, everyone! I just put My Lan to bed and am waiting for the family to get back from the airport, so I thought I’d provide an update. My study schedule has curtailed my tinkering but hasn’t extinguished it entirely. I’ve been slowly making little changes and cobbling together a RIMS (Recirculation Infusion Mash System). The past four weeks of IR and nights has left me with many hours that were too odd to study but too scattered to sleep, so I managed to wrap much of it up. Conical Bliss Before moving on to the news, I’d like to report that the conical fermenter is working great. I’ve read mixed reviews about the plastic conicals, and getting the conical into the cabinet with a clean-in-place configuration was no small feat. The convenience of 10 gallon batches, precise temperature control, and rapid kegging have proven worth it after only two batches. Watch how quickly I can fill a 5 gallon keg! RIMS Mounting I took my seasoned 5400 W Camco heating element and mounted it in a 1.5″ stainless pipe. There’s a 1.5″ cam lock fitting for easy inspection. There’s also a 1/2″ thermowell mounted at the outlet for a 1/4″ temperature probe. The whole unit is mounted on a plastic cart from Harbor Freight, secured with cushioned stainless pipe hangers from eBay and 3/8″ stainless bolts cut to fit and secured to the cart with my Chugger pump and the control box. It’s Probably Big Enough The enclosure has been a difficulty of its own. I underestimated the size of the L6-30 plugs I use for the 240 VAC connections since the circuit has to handle 25 A, so I had to make housings for the plugs only. You can see those monstrosities hanging off the bottom of the enclosure. Actually contained within the enclosure are a switch (on the left), an AGPtek PID controller, and an SSR with heat sink. The PID controller will eventually be substituted for a custom board, but that’s a project for the future. Magic Smoke The SSR was also a frustration. I initially bought a Fotek SSR-40A, but it failed on its first cycle, giving up its magic smoke immediately. My expectations of evidence are high, so I grabbed the fire extinguisher and tried it twice more. When it looked like Independence Day in the enclosure, I concluded confidently that it was broken. I ordered a higher quality Berme brand 40A SSR, and it passed the initial test with flying colors. Wires and Circuits and Breakers, Oh My! Lastly, I swapped out the 30 A dual pole circuit breaker for a similar breaker with a ground fault circuit interrupter. GFCI is a safety feature that breaks the circuit if there is a current outside the electrical circuit, for example, through your heart. These are the same devices on the plugs for blow dryers that have Test and Reset buttons, and they’re good to use in circuits that are near conductive fluids like wort. I’ll be brewing a Belgian-Style Stout this weekend
The recipe for beer is pretty simple. One important step is boiling the wort, the sweet mixture that yeast will ferment into beer. Boiling sanitizes the beer so that yeast can work its magic, but not before the wort is cooled back down or the yeast meets the same quick, steamy end as its potential competitors. There are many ways to cool wort, but I recently upgraded my cooling technique to the optimum method: countercurrent heat exchange. I previously used this immersion cooler. This is a good method in which a length of coiled tubing is placed into the wort. Cool water is pumped into one side and it comes out hot on the other, all the while cooling the wort. Despite the ease of execution of an immersion chiller, it’s limited. Initially, there is a large temperature difference between the wort and the cold water running through the chiller, and it works well. As the wort cools, the temperature difference between the wort and the water decreases, and the cooling is less effective. It takes more and more water to accomplish the same heat transfer. Countercurrent exchange doesn’t suffer this limitation, and this is why it’s a superior heat transfer method. How it avoids this limitation can be demonstrated by comparing the countercurrent configuration to the parallel configuration, which is somewhat similar to the immersion chiller method. Here’s a diagram showing both flow configurations: Both involve a tube within a tube. The inner tube is usually made of thin metal so that the fluids can easily exchange heat across the metal. In the parallel configuration, hot wort is introduced at the same side as cold water. As the wort and water flow through the tube and exchange heat, they approach the same temperature you would get if you mixed the two in a bucket (ignoring the thermodynamic effects of mixing). In the countercurrent configuration, hot wort is introduced at one end and cold water is introduced on the other. This results in a very different temperature profile for each fluid along its path. Check out this diagram from Engineering Toolbox: The result is that the wort is continuously cooled throughout its path while the cold water is continuously heated throughout its path. To phrase this more practically, you more fully utilize the cooling ability of all the water you use. Unlike the immersion chiller that only heats the first amount of water to near the starting wort temperature, all the water used in a countercurrent heat exchanger will be heated near the starting wort temperature. While countercurrent heat exchange is limited by the surface area and the flow rates, so are other methods. For any exchange method, too small a surface area or too high a flow rate and the fluids don’t have a chance to exchange enough energy. Countercurrent exchange is not equilibrium limited, and this is the difference. Countercurrent exchange isn’t just an engineering technique. It evolved biologically and is evident in many homeostasic mechanisms. My favorite is the kidney, an analogous example of countercurrent mass transfer. Remember those tubules and the sodium gradient? That’s countercurrent
It’s ready for a test drive. The conical fermenter is assembled and in place, ready to make some delicious beer with the convenience of a commercial brewery. The last part needed was a clean-in-place system. Since my fermenter is so challenging to get in and out of its mounted position in my cabinet, I need a way to clean and sanitize it without taking it out for scrubbing or shaking. The solution is a system that vigorously sprays the inside of the fermenter. I fiddled around with a homemade apparatus, but quickly abandoned it for something more reliable. I got my hands on a rotating spray ball from Brewer’s Hardware. This fitting has a ball with biased slots. The slots spray fluid from the ball and are configured so the flowing fluid rotates the ball, cleaning the tank wall. I tried attaching the spray ball to a few small pumps including my Chugger pump, but the flow rate wasn’t sufficient. The ball barely sprayed and didn’t spin at all. I had to get a high volume, intermediate pressure sump pump from Harbor Freight. I mounted the spray ball in the lid of my fermenter along with a check valve to prevent negative gauge pressure in the tank during draining, and I gave it a test. Watching it from the outside is important and useful, but it’s a little dull. I decided to get a better view of the action with my GoPro – if only for entertainment purposes. Once it was working, I realized that I have no planned additions to the fermenter for a few years. Thus, it was time to mount it in the cabinet! It was tricky, but once I figured out how to slip the collar in place it was a piece of cake. Now it just needs some wort, yeast, and a little time.
Trang and My Lan were out of town over the weekend. While I’ve mostly forgotten what it’s like to have the place to myself, I did manage to keep busy working on an academic manuscript and, of course, the brewery. Between the broken cabinet fan, the conversion from thermoelectric chips to a tube mounted water heater, and the conical installation, the cabinet has been in pieces for weeks. Fortunately, it’s slowly coming back together. I replaced the thermoelectric chips with a water heater mounted in a stainless steel tube. It’s only a 1200 W element but is much more powerful than the chips. I tested the system at only 1% power and the fluid temperature increased 10 degrees Celsius in about 30 seconds. Nuclear winter won’t keep me from my ales. I’ve also gone back to a smaller aquarium pump in a bucket. The Denner magnetic drive pump I had in place before was a little noisy and overpowered, so I’ll reuse that for my clean-in-place system. The bucket mounted pump is quiet, adequate for the system (I measure a flow rate of 30 mL/s), and can fit inside the refrigerator. Putting the fluid reservoir in the refrigerator might also allow me to make cooling more efficient. Secondly, I redid the wiring for the whole system. I run the power for the pump and heating element directly through the wall of the refrigerator. The thermosensor wiring is all new, with pre-terminated RJ-45 cables that don’t have to be secured with rubber-bands to maintain a connection. They’re all connected through my OneWire hub circuit board and providing reliable signal. I just need to tidy up the cables. The cabinet fan still doesn’t work although I’m sure the controller is providing power. The immersion coil may make the cabinet radiator obsolete in the summer, so I’m not in a hurry to fix it. Removing the thermistors frees up a second fan terminal for the controller, so I may put a large fan into the refrigerator to increase heat transfer at the copper coil inside. I’ll wait until I can run a cooling test with the conical in place to see just how cold I can get 5 gallons of water. Once my CIP fitting arrives, the conical will be ready to go into the cabinet. I’ve put my Chugger pump on a temporary mount. All I need is to put my burner on wheels and finish the counter-flow heat exchanger, and the back end of my brewery will be finished!
I finally pressure tested my fermentor!Several brewers have made conical fermenters using plastic tanks. These tanks have the benefit of a valve at the very bottom. This allows the removal of trub (dead yeast) without transferring to a whole new vessel. The disadvantage is setting up a conical fermenter takes a little more work. Using a simple ball valve on the bottom is problematic. Ball valves have a recess between the body and the ball that collects fluid. For sanitary operations, these would have to be sanitized with heat and occasionally disassembled. A superior approach is a butterfly valve. These valves have no recess to collect fluid, but are mechanically more complicated since the disc has to mate with a gasket. They’re typically much more expensive, but I found a couple of beautiful 1.5″ stainless butterfly valves with silicone gaskets for nearly nothing on eBay. A couple of tri-clamp adapters from Glacier Tanks and a 1.5″ camlock adapter from ProFlow Dynamics makes my valve assembly. Unfortunately, this is where things got tricky and delayed the project. I failed to account for the length of this valve assembly when designing my Fermentation Cabinet. I also designed the doors of the cabinet to account for the tank but not the metal frame. To make an embarrassing story short, I attached hooks to the tank walls for hoisting it into place using small pulleys in my cabinet. The hooks are attached with stainless bolts and washers, which are internally sealed with 1/4″ silicone o-rings and gaskets I made using silicone sheet and punch tools. I built a simple frame into which the tank is lowered in the cabinet, giving enough clearance for the valve assembly. I also wanted to add an immersion coil, something I haven’t seen anyone do with a plastic conical yet. This will make my temperature control system more efficient since I’ll pump the heat exchange medium (I use water) directly through the tank instead of heating or cooling the air around the tank. I got some 3/8″ stainless tubing on eBay that sat in someone’s closet for a couple of decades and a couple of stainless compression fittings. I discovered two things when making this coil. First, bending stainless tubing is not easy! I invariably end up bleeding every time I do it. I wasn’t able to make perfectly smooth bends in the long segments, but the small kinks are only cosmetic and may even improve overall heat transfer by adding turbulence. Second, the walls of the plastic conicals are thicker than stainless vessels. Getting the male NPT fittings through the vessel wall required NPS locknuts from Bargain Fittings. I also wasn’t able to place a washer between the camlock adapter on the external side and the tank. I’ll just have to hope it doesn’t break. I also added a camlock adapter below the liquid level for a temperature sensor and another near the top for a blow-off tube. Finally, I pressure tested the vessel by filling it to the brim. There weren’t any leaks
In designing my all grain setup, I decided to go the route of the Recirculating Infusion Mash System (RIMS). The Heat Exchanger Recirculating Mash System (HERMS) seems like the best route for most brewers, but it’s hard to beat a RIMS if the main objective is automation because RIMS is doesn’t suffer the lag time that a HERMS does. I’m also trying to create a configuration that excludes the hot liquor tank and uses a cold water supply. For sparging, this will require single pass heating, so I’ll need a high power element to accomplish acceptable sparge rates. Gas fired systems seem interesting, but electric is simpler and, in my hands, probably safer. I haven’t seen any home brewer use anything but home water heater elements. A common problem discussed in the forums is galvanic corrosion of components of the heating elements. Even the higher end elements made of corrosion-resistant alloys (Incoloy) have carbon steel threaded bases that are reported to corrode. Most brewers seem to deal with this either by vigilantly keeping the element dry when not in use or by using a sacrificial anode. The folks at The Electric Brewery advocated the former method, but recently updated their website to reflect new Camco heating elements that have stainless steel bases. There are also a few other sites that have stainless heating elements in 304/316 stainless. This is now the way to go. I couldn’t find these elements when I was building my RIMS, so I decided to try something I didn’t see in the forums. I was contemplating how to deal with the problem on Thanksgiving. I’d just received an infrared cooker as a gift and had seasoned it the night before per the instructions. I’m not stranger to seasoning cookwear. It’s a great process that polymerizes vegetable oils onto the surfaces of your cookwear using low heat. The resulting layer of “seasoning” protects iron cookwear from corrosion. While drinking a beer and cooking a turkey, I wondered if the same would be possible with a RIMS heating element. The next day, I prepared two heating elements. I had a smaller element that I was preparing to replace the thermoelectric chips in my cabinet build, which turned out to be underpowered. This element is not stainless steel. The larger element is a 5400 W Camco, which is Incoloy. I drilled 1-1/4″ holes in two cover plates for cylindrical conduit boxes, placed the elements through, and secured them tightly in place using 1″ to 1-1/4″ NPT stainless bushings. I coated the heating elements from tip to base with peanut oil and tried to give the electrical terminals a little protection with some aluminum foil, which I knew would be of limited utility. I put them in the oven and cooked them at 450 degF for about an hour. The seasoning coated the elements and their bases reasonably well. This is appreciable as an amber coating on the elements and their bases in both photographs below. As expected, the plastic protection surrounding the terminals melted. This was easily fixed