Friday, 31 August 2012

STC 1000

I posted this on the AHB forums a while ago, but forgot to put the details here.

A STC-1000 is a single set point digital temperature controller, it's cheap, easy to use, relatively easy to setup and a very useful bit of gear for a range of home brewing and other uses where precise temperature control is needed.  The controller has outputs for both heating and cooling (and will automatically switch between them as required) while cheaper but similar models are available that manually switch and control only the heating or cooling circuit.

A STC-1000 combined with a refrigerator/freezer and heating device (like a heating mat or even a light globe) can be used to control the temperature inside a fridge or freezer at temperature ranges outside what is provided by the internal thermostat.  This makes it ideal for fermenting beer or cheese maturing.  In electric powered breweries it can be used to control the temperature of the hot liquor or boil and even in a HERMS/RIMS system (but a PID is more accurate).  It can also be used with a hot water urn or similar water-heater to make yoghurt or cheese as well as a cheap and easy (but still very accurate) cooker for the increasingly popular sous-vide method of cooking.

There are various ways to setup and install a STC-1000, but the easiest way I have found is to use the plugs from an extension cord and then it's just a matter of housing it in an enclosure.  Obviously when dealing with mains electricity there are logical and legal reasons why this is not a good idea to do yourself.

This is what was used on the most recent (of 4) STC-1000's that I setup:
STC 1000 ($20 Ebay)
3 point terminal block ($1 for 12 point Ebay)
3x PG11 cable glands ($6 for 20 Ebay)
2x 3m extension cords ($3 ea Kmart)
Enclosure (click-storage container $2.50 Coles) - a black jiffy/hobby box is most often used, especially if there are children around that might want to 'investigate' what essentially looks like a 'lunch box'.

A step-bit is useful to drill holes in enclosure for cable glands, and a drill bit for the temperature probe hole:
Cable glands are not essential, but they do look neater and are a little better than knotting the cable or using cable-ties.

The cut-out for mounting the STC 1000 is a little rough but it does not have to be perfect since it won't be seen:

Power cables are cut to length (don't make them too long or they get in the way) and wires are stripped:
The wire colours seen here correspond to the Australian standard for internal household devices.

Fit the cable glands, push the cables through, and attach the wires to the terminal block (the terminal block is not essential but it makes it quicker, neater and safer to setup), the earth and neutral pass through the terminal block and to the output cables:

When in operation the STC-1000 acts as a relay to switch on/off either the hot or cold side of the controller as required, so the active wire is switched via the controller's hot and cold termials:

Once that is done, ensure there is no tension on internal wires (and that they are securely attached) and mak things look neat before tightening the cable glands.  Cable-ties for are useful for tension-relief on temperature probe:

Then it's just a matter of attaching the lid (use tape or screws so it cannot come undone) and labeling the hot/cold cables:

The fridge or cooling device is plugged into the 'cooling' control, and the heat-mat, urn, HLT or other heating device  is plugged into the 'heating' control.  Once it's plugged in and turned on, the temperature can be set via the digital controller, and when the set point temperature is reached, the controller will turn on/off the heating or cooling controls as required in order to maintain the system at the set temperature.

Saturday, 25 August 2012

Baby Fridge

The newest brewing related hardware addition is a little Baby Fridge (Haier 55 Litre Bar Fridge).  The little fridge should be just the right size for yeast starters (the general house temperature tends to be too cold in winter and to hot in summer), cheese making and maybe even keeping some English Ale at 'warm' beer drinking temperatures (10-12degC).
Like the keg fridge, the little Baby Fridge's thermostat is broken and so the compressor runs all the time and freezers everything inside.  Unlike the keg fridge, the Baby Fridge was not a freebie, but not too many people want 'broken' fridges so it cost only $10 - via Ebay.
Since the fridge will be hooked up via a STC 1000 temperature controller, the fact that the fridge is 'broken' is more an advantage than a disadvantage.

In order to provide more floor space and usable room inside the fridge - for starter flasks and large containers - the door-shelving was removed.  The plastic liner is easy enough to cut with a sharp Stanley-knife.
Gaffer-tape should seal the insulation without problem.
The freezer compartment door was removed and the cooling-plate bent along the top of the fridge so that it takes up less room.  The broken thermostat, plastic housing and temperature probe, were also removed.
The fridge-internal-electrical's don't need to be changed in order for the external controller to work.  Usually it's just a matter of turning the thermostat to maximum-cold and letting the STC1000 do the work.  But the Baby Fridge's thermostat/housing got in the way of re-positioning the cooling plate so it was just as easy to remove it.
Since the thermostat is essentially a switch, it's easily bypassed by cutting and then shorting the wires.

The Baby Fridge now fits a 5L starter-flask which it didn't before the modifications.

Thursday, 9 August 2012

Brew Day: German Pils

I picked up a couple of mercury thermometers at Science Supplies so that I could calibrate the various thermometers and temperature probes through the brewery.
As it turned out the PID temperature probe was reading about 2degC above the actual temperature, the mash-tun's dial temperature probe was close enough to be accurate, and the TempMate and cheap digitial thermometers were within about 0.5degC at most temperatures measured.

Insulating the converted kegs and silicon hose goes a way to help keep temperatures stable, however, the insulation on the hoses made them unwieldy and difficult to work with.  They were also impossible to clean by simply throwing them into the kettle filled with cleaner.  These little velcro straps (usually used to tie computer/electrical cables) seem to work well to hold the hose insulation in place, while also allowing it to be easily removed when required.

The little-brown-solar-pump decided to stop working mid-brew - again.  This time I disassembled it and cleaned it well inside - likely something that should be done every brew - given the amount of crud inside especially inside and around the shaft and housing.
Since the other little-brown-solar-pump is broken, I was quite relieved when this one worked again, not sure if it worked because it was cleaned or simply because it was allowed to cool down for 30 mins.  While they are cheap, I'm starting to think they are not worth the trouble, and will need to upgrade to a more substantial and dedicated brewing pump soon.

Although my fermenting fridge can only fit two fermentors, allowing for several weeks fermenting then at least four to lager, if I want to get lagers things finished before October, I have to get them fermenting soon.  For the moment I'll put this latest lager into the keg-fridge and then work out what to do after that - it's possible I'll lager each of the beers in the smaller corny-kegs, or even plastic-cubes, rather than in the fermentors like usual.

This German Pilsner has a very similar grain bill to the BoPils, however the German hops and Calcium Sulphate will likely give it more hop character.  Using the HERMS to step the mash temperatures will also be easier - and make the brew day shorter - than using decoctions.
German Pilsner
Estimated OG: 1.049 SG
Estimated Color: 3.4 SRM
Estimated IBU: 42.8 IBU
Boil Time: 90 Minutes

Pilsner (Best Malz) 96 %
Carapils (Weyermann) 4 %

Northern Brewer (11) (60 min) 17.4 IBU
Pearle (HG 12) (60 min) 9.3 IBU
Tettnang (HG 12) (60 min) 5.0 IBU
Pearle (HG 12) (30 min) (0.52g/L) 4.8 IBU
Hallertau (HG 12) (15 min) (0.42g/L) 1.5 IBU
Hersbruker (HG 12) (15 min) (0.42g/L) 1.3 IBU
Hallertau (HG 12) (5 min) (0.83g/L) 1.9 IBU
Hersbruker (HG 12) (5 min) (0.83g/L) 1.7 IBU
Hallertau (HG 12) (0 min, hop-back) (0.42g/L)
Hersbruker (HG 12) (0 min, hop-back) (0.42g/L)
Tettnang (HG 12) (0 min, hop-back) (0.42g/L)

Whirlfloc (Boil 15.0) (0.042g/L)
Yeast Nutrient (Boil 15.0 min) (0.042g/L)
Lactic Acid (Mash 60.0 min) (0.084ml/L)
Calcium Chloride (Mash 60.0 min) (0.17g/L)
Calcium Sulfate (Mash 60.0 min) (0.33g/L)

Mash In, Protien Rest (3.4L/kg) 55.0 C 15 min
Maltose Rest 61.0 C 45 min
Dextrinization Rest 70.0 C 45 min
Mash out 76.0 C 10 min

Bavarian Pils (BrewLab #5705) (18.75billion cells/L)

Pitch @ 8 C, Ferment @ 10 C
Since the Style Guidelines specifically mention Tettnang hops, the plan was to use them in place of Perle that were used in the Dortmunder.  However, even though they were picked and packed only a few months ago, the Tettnang smelled dusty and lifeless when they were opened, while all the other hops were nice and aromatic - so it's possible they were not picked, dried or packed in a way that helped retain their freshness.  Since I had them open and weighed I threw the Tettnang in early and late, but added the much nicer/fresher Perle at 60 and 30mins.

With the additional whole hops, there was quite alot of hop debris remaining in the kettle at the end of the boil (it smelled good too):


Unfortunately - or fortunately - will see when the beer is fermented - the little-brown-solar-pump decided not to turn itself back on right after the mash was ramped up to the Dextrinization Rest temperature, and took about 30 mins to get working again.  Since not all the mash was up to 70degC, I expect that the consequence might be a more fermentable wort than was planned, hopefully that will still fit with how a German Pilsner should be.

Other than the pump-failure the brew day went well, and for the first time on the new system, the volume into the fermentor was exactly as anticipated.  The gravity was within 1 gravity point of what was calculated and so it would appear that I have most of the parameters of the new system worked out.  I plan to narrow the mill-gap on the next brew, because it's possible that not all of the grain is getting crushed fine enough and so a small efficiency gain might be possible.

Letting the wort chill overnight before removing it from the break and pitching yeast might pose a small risk, however, pitching at low temperature should help minimize any yeast-off-flavours and also gives very clear wort into the fermentor:

Monday, 6 August 2012

Brew Day: BoPils

Ideally I'd like to get each beer into the fermenting fridge as soon as possible, however the exact schedule is dictated somewhat by the yeast propagation process, which takes some time since each yeast strain is propagated from a slant into a 4.5L starter.  Usually I'd repitch the rinsed slurry into the next batch of beer but this year a new yeast and starter will be used for each.
Fresh yeast slants were made for each strain and stepped into a 100ml starter, up to about 600ml and then to 4.5L.  The first two steps take about a 24 hours, which should be more than enough time for the yeast to grow as much as it's going to.  The last 4.5L starter is grown on the stir plate for 24 hours, before being left to complete the fermentation process and settle out, which usually takes another 24hours.  As the yeast starts to settle, the batch of beer it will be pitched into is brewed.  That way once the beer is brewed, chilled and ready for the yeast to be pitched, the yeast will have finished fermenting the starter, settled to the bottom of the flask ready for the spent starter beer to be decanted.

The plan for this Bohemian Pilsner is to brew it to a slightly lower gravity, but with significantly more hops (quantity rather than IBU) and additional malt-balance than last years.  The hop character should be enhanced by using Saaz in all additions, including a number late in the boil, however most of the hops (09 Czech Saaz) are a little older and so using extra is probably a good thing anyway.
BoPils
Estimated OG: 1.054 SG
Estimated Color: 3.5 SRM
Estimated IBU: 42.8 IBU
Boil Time: 90 Minutes

Pilsner (Best Malz) 94 %
Carapils (Weyermann) 6 %

Saaz (09) (First Wort Hops) 15.8 IBU
Saaz (09) (60 min) 14.3 IBU
Saaz (09) (30 min) (1.25g/L) 6.9 IBU
Saaz (09) (30 min) (1.25g/L) 3.6 IBU
Saaz (HG 12) (5 min) (1.25g/L) 2.2 IBU
Saaz (HG 12) (0 min, hop-back) (1.25g/L)

Lactic Acid (Mash 60.0 min) (0.084ml/L)
Calcium Chloride (Mash 60.0 min) ((0.033g/L)
Calcium Sulfate (Mash 60.0 min) ((0.042g/L)
Lactic Acid (Sparge) (0.0001 ml/L)

Mash In, Acid Rest (3.6L/kg) 35.0 C 30 min
Decoct 30%
Protein Rest 53.0 C 15 min
Saccharification 63.0 C 35 min
Decoct 20%
Saccharification 71.0 C 35 min
Mash out 76.0 C 10 min

European Lager II (Wy2247) (18.75billion cells/L)

Pitch @ 8 C, Ferment @ 10 C
The decoctions added a significant amount of time (about an hour) for each step (they were used), so it was skipped at the Protein Rest so that the (modified) malt was not held too long.

Decoctions were taken such that they were comprised of the thick (mostly grain) portion of the mash:

Using the a special (ie: broken) decoction jug:

Which actually works well, because the mash liquor drips from the bottom of the jug back into the mash while retaining the grains:

Each decoction volume was chosen so that when it was returned to the mash it would bring the temperature up slightly below the next step temperature,  with the adjustment made via the HERMS.  The decoction was heated to Saccharification temperature (65 to 70 deg C) and held for about 15mins:

Before boiling for about 10 mins:

A little care needs to be taken when heating the decoction - which was done on the stove, in an 11L pot - so that the grain does not stick and burn onto the base of the pot (hence the spoon in the pictures above).  Once the decoction was at boiling point, it did not need any additional attention:

With a portion of the mash removed for each decoction, the mash tun looked a little empty:

As mentioned earlier, while the overall IBU's should come in somewhere about 43, there is actually a fair weight of hops in this recipe:

As the wort was drained/pumped from the mash into the kettle, it was time to add the first of the hop additions (First Wort Hops):

As the last hop addition was added, the plate chiller and hoses are sanitized by running boiling water from the HLT through them:

Then the kettle is drained into the hop back, pumped from there through the plate chiller into the fermentor, into the fermentor the wort temperature was about 14degC:

Unfortunately - since I was making spaghetti bolognese at the same time - I forgot to add both the Whirlfloc and yeast nutrient.  The yeast nutrient can be added (with a little bit of boiling water) directly to the fermentor when the yeast is, but hopefully the lack of Whirlfloc will not be too bad, into the fermentor the wort didn't look too bad:

The fermenting fridge already has beer in it, so I had to borrow the keg-fridge over-night so that the wort could be chilled  ready for the yeast to be pitched in the morning:


Brewery Build #23: Kettle Volume Markings

Guessing the how much wort was in the kettle pre-boil was a little difficult - but it's an important thing to know.  In order to know how much wort is drained from the mash tun into the kettle, volume markings were added to the inside of the kettle.

Since it cost only $3, I was not sure that the Ebay-supplied (bobowaytoway)  'Etching/Engraving Pen' would work for the purpose:

However the little 'Engraving Pen' did a good job to engrave the volume markings on the inside of the keggle:

The first few times it was used the PID was not very accurate, tending to over-shoot and then holding the temperature 1 or 2 degrees above the set value.  Likely this was because the unit had not been tuned to the system it was being used in, however the instructions for this process provided by SESTOS were not very helpful or clear in how to perform the auto-tune
"First operate the Auto adjustment, press AT key 2 second, SV display blink AT, finally into PID control mode. Press the AT key 2 second to abandon Auto adjustment."

Luckily one of the reasons I purchased the SESTOS unit is because (not only was it cheap) but functionally it's so close to the Auber PID that the clear, detailed and easy to understand Auber PID instructions can be used.
What they explained was that:
By default auto-tune is not enabled.
To enable the auto-tune function one must enter the settings-menu and change the 'CtrL' setting (called 'At' by Auber) from 3 to 2.
Once this is done the PID will enter auto-tune mode where it will configure itself for the system.

Now that the auto-tune has been run successfully, the PID holds the mash-temperature to within about 0.2 deg C of the set value - which is considerably better than it did previously:

Saturday, 4 August 2012

Brew Day: Dortmunder

While the cold winter weather is here - even if heading into August is a little later than I'd have liked - it's an ideal time to brew some lagers.

Last years winter-brewed batch turned out quite well.  BoPils ...
... Munich Helles ...
... and a Vienna Lager.
... so hopefully the ones brewed this winter will be just as good ... or better.

First up this winter is a Dortmunder, the Style Guidelines suggest a balanced smooth beer, with the malt profile of a Helles and hop character of a Pils. The Guidelines are also very specific in recommending minerally water to accentuate hop bitterness, but current brewing practices in Dortmunder indicate that they treat the water so that it is much softer than the Guidelines suggest.  So I added what will hopefully be just enough brewing salts to make an impression but not enough to go over-board, I also added a fair amount of late kettle and hop-back hops, but since they are home-grown whole hop cones, I don't expect they will be too much.
Dortmunder
Estimated OG: 1.056 SG
Estimated Color: 4.9 SRM
Estimated IBU: 30.7 IBU
Boil Time: 90 Minutes

Pilsner (Best Malz)  70 %
Munich I (Weyermann) 12 %
Vienna Malt (Weyermann) 12 %      
Carapils (Weyermann) 5 %      
Melanoidin (Weyermann) 1 %

Northern Brewer (11)  (60 min)  17.4 IBU
Pearle (HG 12) (60 min)  11.2 IBU
Hallertau (HG 12) (10 min) (0.42g/L)  1.1 IBU
Hersbruker (HG 12) (10 min) (0.42g/L) 1.0 IBU
Hallertau (HG 12) (0 min, hop-back) (0.42g/L)         
Hersbruker (HG 12) (0 min, hop-back) (0.42g/L)

Whirlfloc (Boil 10.0) (0.042g/L)
Yeast Nutrient (Boil 10.0 min) (0.042g/L)
Lactic Acid (Mash 60.0 min) (0.042ml/L)
Calcium Chloride (Mash 60.0 min) (0.208g/L)
Calcium Sulfate (Mash 60.0 min) (0.208g/L)
Lactic Acid (Sparge) (0.011 ml/L)
Calcium Carbonate (Boil 90.0 min) (0.042ml/L)

Mash In, Beta glucan Rest (4L/kg)  40.0 C  20 min
Maltase Rest  63.0 C  35 min
Dextrinization Rest  71.0 C  35 min      
Mash Out  77.0 C  10 min

Danish Lager (Wy2042) [Starter]  ( 18.75billion cells/L)

Pitch @ 8 C, Ferment @ 10 C
The mash schedule was taken from information posted on one of the home-brewing forums from a commercial brewer, as was the details about not going too far with the brewing salt additions.  All very light grains given the expected light-golden colour the beer will be:

Pre-boil volume was 32L - the new graduations on the kettle helped get this volume exact - but even with only 1 element turned on the break was almost escaping the 50L keggle:

Testing a slightly different - but still very temporary - configuration for the 'brew stand', placing the HLT on the end and not the middle should make building a permanent stand easier, so I wanted to test it first, but still don't know the best place to put the control-panel.

The disadvantage in using a plate-chiller to cool the wort is that the cold-break material ends up in the fermentor.  In order to help remove this break material to help achieve the cleanest/clearest beer possible and to drop the wort down to lager yeast pitching temperature (8 deg C) the fermentor was stored in the fridge overnight:
In order to minimize any thermal-shock, the yeast was also stored in the fermenting fridge with the cooled wort (both the yeast and break material can be seen settled at the bottom of the two vessels).

The next morning the wort was transferred to a new fermentor, aerated and the yeast pitched:

Leaving most of the break material behind:

About 12 hours later, the yeast had already formed a nice krasuen, which is hopefully a good indication that enough fresh/healthy yeast was pitched.

This is especially important since the temperature will be held at about 8 or 9 deg C for the first couple of days of the fermentation process, before the majority of the fermentation will be at 10 deg C.  After that the beer will be lagered for some weeks at about as cold as the old fridge can go (about 1-2 deg C).