Temperature Monitoring with Arduino

First off, I’m sorry it’s been so long since I’ve updated anything – I’ve been pretty busy.

I’m just finishing up the nerdiest project I’ve ever undertaken.  The backstory: I’ve been unsatisfied with my bimetal thermometer for reliable measurements.  I was looking in to buying a nice digital thermometer when I found that the parts for those are ridiculously cheap.  So I decided to build my own thermometer.  But since I’m not a reasonable person, I decided that rather than have a simple digital readout, I’d like the temperature to be sent to my computer at regular intervals, so that I can track it over time. 

All of this is accomplished with the Arduino, a great little nerd toy which does most of the work for you:

It connects to a computer via USB and needs no external power.  It has a bunch of input and output pins and can be programmed to do a whole lot of things.

I decided to build three temperature sensors for monitoring fermentation temperature and one for monitoring mash temperature.  I used three thermistors (10k) and one LM34 sensor.  I placed each inside of a homemade stainless steel thermowell.  All are connected with ethernet cables, which provide a nice way to plug the sensors in to a gutted router box, which holds the Arduino:

Basically, the thermistors and LM34 alter the voltage depending upon the temperature.  They are connected to the analog input pins on the Arduino, which simply reads the voltage off of each pin and sends it over USB to the computer, and my program then interprets each voltage to obtain a temperature reading. 

Wiring of thermistor:

LM34 wired and heat-shrink wrapped:

Finished temperature sensors inside thermowells and with carboy caps (I used silicone sealant to seal everything):

… And the readout on the screen:

The readings are a bit off, because the sensors haven’t been calibrated for the ten feet of wiring.  The program is capable of using Excel’s xml format to import the temperature data directly into Excel, where I can make charts, etc.  I plan to use this on my next brew – I’ll post results!

Homebrew Festival

The Homebrew Festival is back.  This time it’s taking place at the Night Light in Chapel Hill.  Mandolin Orange and Black Swamp Bootleggers will be playing, and there will be plenty of homebrew for tasting.  For more information see:

http://www.worldhomebrewfest.com/  – General Info

http://worldhomebrewfest.eventbrite.com/ - Tickets

PSA

As a warning to all brewers – please be sure to tighten all keg fittings.  I left a newly full keg hooked up to the gas with the liquid line loose, and the entire keg emptied itself into my chest freezer.  True sadness is scooping cups of your beer into a bucket and dumping the entire 5 gallons into the sink.  I don’t have a picture, but I’ll let you imagine the awful mess.

As consolation, I brewed up a chocolate espresso stout, recipe to be found here.  The boil took an extremely long time, because of the large amount of grain and thus high volume of wort collected from the mash.  I’m pretty excited about this one.

The Carrboro HomeBrew Festival is having another event in February.  If you are a brewer, please sign up to brew for the event.  It’s a great time.  Here are some details:

On February 20th from 4-9, we are organizing another Carrboro Home Brew Festival to benefit the fight against multiple sclerosis. Our last event was a great success with over 150 people in attendance, 18 different kinds of home brew available for tasting, three bands, and some guy who did fire juggling. In order to make this next event happen we need your home brewing expertise. Guidelines have not been completely worked out yet, but basic requirements to enter are to brew one 5 gallon batch of beer, sign up on our eventbrite website, http://worldhomebrewfest.eventbrite.com/, and bring your brew, in keg or bottle, to the event. The winner of the beer tasting will get a inscribed glass mug as well as other prizes that are to be determined. For your help in brewing beer for the event, we will give you a ticket to bring a guest, you can come an hour early to taste the home brew and mingle with fellow brewers, and we will provide dinner. We have not decided upon a location or judging guidelines but we will keep you updated.

Sorry for the relatively short post – things have been busy here.

DTH Feature

Pardon the shameless self-promotion… UNC’s student newspaper, The Daily Tarheel has a new beer blog, “Brew-Ha-Ha.” I’ve been featured as a home brewer there: http://www.dailytarheel.com/dive/brew-ha-ha-home-brewer-profile-eric-boren .

Brew Club

I’m heading up the formation of a home brewing club here in Chapel Hill.  There seem to be a lot of brewers in the area, and I think it’d be a lot of fun to get together as a group.  The first meeting is tentatively scheduled for Sunday, November 22, from 4-6 pm.  We’ll be giving out info at the Home Brew Festival on November 7th, and the date will be verified by then.  I have a website for the club which is temporarily located on my UNC webspace: http://www.unc.edu/~boren/chchbc.  It’s far from done, and it’ll be moved once the club gets going enough to fund the purchase of a domain name, but it’s got the important information.  If you’re a brewer in the area, definitely check out the site, and consider coming to the first meeting. We’ll be giving away a six pack of beer to the person who comes up with the best name for the club, so be thinking of ideas.

New IPA

I just brewed an IPA, as a consolation for the first brew which turned out so badly.  Here’s the recipe:

Expected OG at 70% eff: 1.064

10 lb 2-row
2 lb Vienna Malt
.5 lb Crystal 60L

Mash @ 152

1 oz Magnum @ 60 min
1 oz Cascade @ 15 min
1 oz Willamette @ 15 min
1 oz Willamette @ 5 min
1 oz Cascade @ 5 min

1 oz Cascade, dry hop
1 oz Willamette, dry hop

52.63 IBU

Nottingham Dry Ale Yeast

… Except that Fifth Season didn’t have Vienna Malt, and I didn’t realize it until I’d already crushed 2lb of Victory Malt in with the rest of my grains!  Duh.  So I brewed it anyway.  It’ll be a different beer than expected, but should still be ok.  I bought hops in bulk (something I’ll probably continue to do), which reduced my price /oz from $2.50-$3.50 to around $.60, from www.hopsdirect.com.  I also used FermCap S for the first time.  It’s a foam inhibitor, and it allowed me to fill my brew pot much fuller than I’d normally be comfortable, without having to worry about a boilover.  I had low-ish efficiency (again) and ended up with an OG of 1.057.  I’ll have to do some detective work to figure out the flaws in my system.  Anyway, it’s in the fermenting chamber, bubbling away with a thin layer of foam.

I also got a temperature controller for the chest freezer.  It’s holding steady between 36F and 44F, which is perfect.  I have an oatmeal stout freshly kegged and carbonating.  I plan to take it and the Belgian Wit, which finished about a week ago, to the Carrboro World Homebrew Festival on November 7th.  If you’re at all interested, you should come out.  Be sure to reserve your free ticket on the website.

New Brew, Kegs, and Fermentation Chambers!

It’s been a while since the last update, and a lot has happened.  We picked up some kegging equipment and now have the Altbier and Apfelwine kegged and carbonated.  The advantage to kegging is that you don’t have to wait for the yeast to naturally carbonate the beer.  A CO2 tank is used to force carbonate.  You also don’t have to clean and fill large numbers of bottles. 

 

Upon tasting the original brew, the “IPA,” we deemed it not to be worth drinking.  It’s definitely beer, but it’s kind of hard to handle.  The expired ingredients, combined with a bad recipe, high fermentation temperatures, and a little bit of scorched malt extract, make it less than enjoyable.  The second brew, the Altbier, turned out much better, but is definitely not an Alt.  It has a strongly fruity estery taste, which is caused by stressed yeast fermenting at high temperatures.  It’s definitely an “ok” brown ale, though. 

 

This led to another equipment addition: two large rubbermaid tubs to be used as fermentation chambers.  I cut holes in the tops for the airlocks to show through, and the tubs will be filled with water and frozen water bottles to keep the fermenting beer cooler. 

 

I also finally converted that gatorade cooler into a more legitimate mash tun.  I followed the directions I linked to on the last post, except that I made a loop of stainless steel braid, for more even draining of the container. 

 

Using the new mash tun I brewed an all-grain Belgian Wit, which went much better than the last attempt.  I used a kit purchased from www.midwestsupplies.com, which has a good selection of reasonably-priced all-grain recipe kits.  The process went very smoothly, but I ended with an original gravity of 1.038, compared to an expected 1.044.  I got about 60% efficiency, which is lower than I’d hoped, but I think it’ll come out fine.  It’s in the new fermentation chamber now.

First all-grain batch

On Friday I brewed our first all-grain batch: a Sierra Nevada Pale Ale clone.  The Recipe: http://www.brew365.com/beer_snpa.php

10 lb 2-row pale malt

1.25 lb crystal 60L

1/3 oz. – Magnum – 60 min.
1/2 oz. – Perle – 30 min.
1 oz. – Cascade – 10 min.
2 oz. – Cascade – at flameout

White Labs California Ale Yeast (WLP001)

Est. OG 1.052

I subbed the Magnum hops for Columbus, and the yeast for Safale US-04, based on what was available at the store.  The important difference between extract brewing and all-grain brewing is that in all-grain brewing, the starches in the grains must be converted to sugars to be used in the wort, while with extract brews those sugars are already converted, and you start with wort in concentrated form (extract) and add to water.  The conversion is done in a process called mashing, in which the grain is steeped in water at a specific temperature (or temperatures) for a specified amount of time.  This recipe called for one hour at 153F.  Most home brewers use some form of converted cooler as a mash tun: http://www.homebrewtalk.com/wiki/index.php/Converting_a_cooler_to_a_mash_tun

I thought I could avoid the extra cost of conversion by using the strainer that came with my brew pot combined with a five-gallon mesh paint strainer bag.  The idea was to line the strainer with the bag, and place the grains in that, inside of the cooler.  This ended up being a big mistake; the grain was just slightly more than could fit in my strainer (should have checked that…).  In order to cover the grains with water, I had to put the water level above that of the walls of the strainer.  This, combined with the fact that there was dead space between the strainer and the cooler wall, resulted in a far-too-high water to grain ratio, which can have a negative effect on extract efficiency (the percentage of sugars extracted from the grains).  Typically, this is called a thin mash, but what I had was a thick mash inside the strainer and a very thin mash outside.  I managed to hit the right temperature, however, even with the extra water additions.  Of course, when the hour was up, I couldn’t drain the wort from the cooler through the spout, because the overflowed grains clogged it.  I “sparged” by adding a couple gallons of 170F water (my volumes were way off at this point).  Then I lined a five-gallon bucket with another paint strainer bag and poured as much wort as would fit into it, pulling the grains out in the bag, and repeated with another bucket.  I took a gravity reading, and even adjusted for the heat was way off.  Something around 1.030, though the calculation loses accuracy when the temperature is high.  The estimated OG of 1.052 assumes 70% efficiency, so I was somewhere below 50%.  Lesson learned. 

Far-too-thin mash

I decided to compensate by boiling for an extended period of time in multiple pots, to boil off enough water to bring the specific gravity up to where it should have been.  At the end of the boil, I had about 2.5 gal of 1.056 wort.  Not too bad, but a huge waste of grain for such a small yield.  Everything else went pretty well.  I pitched the yeast and transferred to the fermentor.  I think it’ll end up fine, but I’m a little disappointed.

Hop sludge

 

Siphoning cooled wort into a bucket

 

In the fermentor

We also cracked open a bottle of our first brew (the IPA) to try it after a week.  It had started to carbonate, and it was definitely beer.  It wasn’t all that impressive.  The bitterness and sweetness were individually perceptible.  I’m thinking this one will need a good while in bottles before it becomes acceptible.  Our newer brews, with fresher ingredients and better recipes, should be better. 

And there’s kegging equipment on the way.

Bottles and bottles and bottles

We’ve hit the next landmark in our first brew - the IPA is done fermenting and has been put into bottles.  We’re using a technique called bottle conditioning to naturally carbonate the beer in the bottles.  Sugar is added to the uncarbonated beer (we used 3/4 cup dissolved in 2 cups of water and then boiled) and then the beer is bottled.  Over the next couple of weeks, the remaining yeast in the bottles will convert the added sugar to co2.  Since the bottles do not have a way for the co2 to escape, it will remain suspended in the liquid as carbonation.

Our first bottle of beer!  We dispensed the beer from the gatorade cooler (which we’ll soon use as a mash tun when we make the jump to all-grain brewing) and capped the bottles using the bench capper seen in the photo.  We then boxed up the bottles and wrapped them in a tarp in case of exploding bottles.  We tasted what was left over, and it was definitely beer, but was a little too bitter and too sweet.  I’m hoping that time in the bottles will mellow the flavors out.  Bottling is a tedious process, because each bottle must be scrubbed clean and then sanitized before being individually filled and capped.  We didn’t have a full five gallons in this brew, so we didn’t have to fill as many bottles, and we were fortunate to have a couple of cases of 24 oz bottles, which reduced the number we had to use.  We’ll open a bottle at the end of next week to see how it’s doing.  If you’re in the area, we’d love to share the first batch with you, provided it’s good enough for us to call it ours.

Altbier brewed…

The Altbier has been brewed and is in the fermentor.  It’s going to be a beer for Oktoberfest, since the traditional Oktoberfest beer (Marzen) is a lager and we don’t have the means with which to lager (cold storage for several months at temperatures just over freezing).  Altbier is a classic German style, brewed almost exclusively in Dusseldorf.  Altbier literally translates to “old beer,” referring to the style (styles?) of beer brewed before artificial cooling and lager (bottom-fermenting) yeasts were available.  The term, then, could apply to a number of styles, but it typically refers to a deep copper to brown colored ale with a light to medium body and strength and a balanced, malty flavor.  I figured it would make a good substitute.

I tried a number of new techniques with this brew, the most important being a full boil.  This means that the entire volume of liquid was boiled, rather than boiling half and adding it to water.  A full boil tends to utilize the hops better, and when brewing with liquid extracts leads to a lighter color (one more appropriate for the style).  The problem with a full boil is that it takes a powerful heat source to boil 6 gallons of water.  I’d tested our stove before, and after 45 minutes the 6 gallons wasn’t close to boiling.  I worked around this issue by boiling three gallons in the large brew pot and boiling one gallon three times in a smaller pot, adding to the large pot after the one gallon was boiling. 

Another new technique I used was a hop bag.  I bought some five-gallon paint strainer bags from Home Depot and before adding hops I lined the inside of the pot with the mesh bag.  This way, it was easy to strain the hop sludge from the bag.  Last time, I lost about a half gallon of wort to sludge.  This time, no problem!  I also siphoned the wort (I realized I never defined this before; wort is beer before fermentation) from the pot rather than pouring it, in hopes of leaving behind some trub and maybe ending up with a clearer beer.

I also used the wort chiller I made for the first time.  It worked perfectly, and the wort was cooled within 25 minutes.

We used a kit this time, with ‘fresh’ ingredients (who knows how long that box has been sitting on the shelf).  I began, as before, with steeping some specialty grains.  I then added boiling water as I heated the brew pot to a boil, until a full 6 gallons were in the pot.  Then, the extract syrup was stirred in (with the pot taken off the heat – this is important to avoid scorching) and dissolved.  I then added the hop bag and began the hour long boil with hops.  The problem with the hop bag technique was soon apparent: the holes in the bag were too small to let the bubbles from the boil pass.  Instead, the bubbles pushed the bag upward so that I had to keep pushing it back down with the stirrer.  At one point, I walked a few feet away for less than a minute, and the bag came all the way to the top.  Since it was wet with malt-water, it dripped down the side of the pot and into the burner.  The smoke alarm went off as soon as the sugar in the water burned on the stove, and I had to rip it off the wall.  I was more careful after that.  The rest of the brewing process went well – I cooled the wort, siphoned it as mentioned before, pitched the yeast, and poured into the fermentor. 

After 24 hours, the beer was fermenting aggressively, with several inches of rocky krausen (fermenting beer foam) on top.  I gawked at it for some excessive amount of time before I could pull myself away.  This should be good.

Now we have three carboys full of fermenting beverages, and all that remains is to wait.  The IPA will be first to go, and will be bottled this coming weekend.  The Altbier and Apfelwine will be ready in a few more weeks.  We’re also working on equipment for kegging, which means we’ll have our beer on tap at home!

From left to right:  Altbier, Apfelwine, IPA

Another thing: As you’re reading and have any questions or comments, please feel free to leave a comment.