Monthly Archives: March 2014

Whirlpool Fever

The Players

Since our boil kettle was first constructed last year we followed Kal’s lead and used a Hop Stopper to filter wort.  This product works fairly well and prevents both hops and some break material from hitting the chiller and eventually the fermenter.  It’s easy to clean with a kitchen sprayer, and is very well constructed.

The Setup

But the Hop Stopper does have some drawbacks:

  • efficiency: quite a bit of wort is left in the kettle. We use sanitary magnetic drive pumps (like Chugger, US Solar, or March) to transfer wort and these require continuous flow with no air pockets, otherwise the pumps lose prime.  When the wort level gets below the Hop Stopper, the hops and hot break clogging the screen prevent wort from getting inside the screen quickly enough, and air gets into the lines instead.  Also, because our kettles are quite large, each gallon is less than 1 inch in height, and the bottom is flat (unlike a Sanke keg), which means that when the wort level drops too low for the Hop Stopper, we still have a full gallon  or two left.
  • babysitting: When the wort level gets too low, you either have to leave wort in the kettle or use a spoon to agitate the hop stopper (by pressing down and releasing every second) to let more wort into the screen.  This does work, but if you’re trying to control the flow through the pump to hit the right temperature, agitate the Hop Stopper screen, and watch for when air starts to enter the pump intake to prevent loss of prime, you’re likely to screw something up because everything is happening at once.  You need five hands, and you’ve only got four, or maybe even just two.
  • whirlpooling: you can’t easily whirlpool since the Hop Stopper blocks the circulation pattern, and picks up from the center instead of the side.  We’re interested in this technique that many traditional breweries use and we’d like to replicate it in our setup.

The Hook

Whirlpooling is the circulation of the wort in the boil kettle after the boil is done to concentrate the hot break, cold break, grain particles, and hop bits into the center of the kettle.  Due to the magic of physics and fluid dynamics solid particles will move to the center when the liquid is stirred and then allowed to settle.  This leaves clear wort at the sides, and with a side pickup in the kettle, allows you to leave most of the solid stuff behind providing clearer wort and eventually clearer beer.

Second, you can use the whirlpool to provide increased hop aroma and flavor by steeping a separate addition of hops while the whirlpool is circulating.  Since during the whirlpool the wort is around 170 – 200°F (82 – 93°C) volatile flavor and aroma compounds are not driven off like they are during the boil.  Many traditional UK breweries use this technique to increase the complexity and clarity of their beer.  We’d like to try it too.

The Tale

The first step was the removal of the Hop Stopper and the addition of a side pickup.  Instead of a traditional dip tube, we decided to use a 90° street elbowwp-before and a barb fitting at the bottom outlet of the kettle.  Besides the whirlpool benefits, during the cleaning process when recirculating PBW after a brew session, we need to drain all the PBW water from the kettle, which is now easily accomplished by tilting the kettle towards the barb.  In short, the new barb fitting allows us to drain almost all liquid from the kettle, whether that’s wort or cleaning water.

Since the barb draws from the side, after the whirlpool has settled all the break material and hops in the center, and only clear wort is left on the sides, we’ll only get clear wort into the fermenter.

Next because we use pumps, we need some mechanism to induce the whirlpool in the kettle.  Yes, we could stir vigorously with a spoon, and we’ve tried that, but it doesn’t work as well as you’d think due to the magnesium anode, the heating element, and the thermometer getting in the way during 5 gallon brews.  Instead, we constructed a whirlpool arm that attaches to our kettle inlet and is easily removed forwp-after increased flexibility.

As you can see, attached to the upper kettle inlet is the new whirlpool arm, which directs the wort along the side of the kettle and induces the actual whirlpool when wort is taken from the kettle and pumped back in.  The bottom level of the arm allows us to still brew and whirlpool 5 gallon batches if we want to.

Why did we choose a camlock fitting for the arm?  Well, when we’re fly-sparging, wort is continuously draining into the kettle and we need to monitor the gravity to ensure it doesn’t drop below 1.010, which begins to extract undesirable tannins from the grain husks in the mash.  The boil kettle inlet is where we collect the sample from, and we need it to be easily accessible, so we’ll only attach the whirlpool arm after the boil is done.  Second, allowing the whirlpool arm to be disconnected helps ensure it can be cleaned well.

The Finale

We don’t actually have a finale yet since we haven’t tried the whirlpool arm in a full brew.  But we have tried the kettle outlet barb fitting, and it works great.  We’ll definitely let you know how the whirlpool arm performs in the next brew.  Stay tuned!

IPA Take Two

We brewed this IPA the first time back in November and we didn’t Brew It Right™.  Time to fix that.

Last Time

November’s grain bill was too sweet and wasn’t balanced by the hops.  When racking to secondary and tasting the hydrometer sample, we said:

Wow, what an awful taste.  First off, too sweet, and the aroma hops (mostly Cluster) just don’t work with the sweetness of the malt.  Maybe it will get better with time, but we certainly know what we won’t do in the future: pair a large amount of Golden Promise with late-addition Cluster.

The beer got better with age, but was never particularly good.  This time, we’re making some changes:

  1. Maris Otter instead Golden Promise – GP is a sweeter malt, but we’d like complexity without the sweetness, thus the MO.  We’re sure GP is appropriate in some beers, just not in this one.
  2. No Cluster – not clean enough of a finishing hop, at least in the large quantities used in IPAs.  While we know of some very popular lighter beers that use late-addition Cluster, it’s just not right for this IPA.  This time we’ll go with more traditional finishing hops.
  3. Add some wheat malt – makes the beer a little lighter and gives better head.  Plus we’ve got some we need to use.

The Brew

Weighing out the grain
A splash of flaked maize makes a great picture

This time we decided to try batch sparging in an attempt to save time during the brew day.  We usually fly-sparge on our system, and that takes anywhere from 60 to 90 minutes, so we were looking to speed things up and make the brew day a bit shorter.

Batch sparge
Sparging the first batch

In a typical batch sparge, you drain the entire mash tun for the first batch.  Then you add more hot water, let it sit for about 15 or 20 minutes, and drain again for the second batch.  The combination of first and second batches makes your final boil volume.

Our first batch clocked in at 5.25 gallons and 13.75 Plato.  The second batch was 3.25 gallons at 6.5 Plato.  With these batches combined, we began the boil with 8.5 gallons at 11 Plato (1.042 SG).  This was right on the target of a final 5.5 gallons at 1.066 SG, but since our boil-off rate is about 2 gallons per hour, we needed to boil off a gallon of wort.

30 minutes later we added the first bittering hops and an hour after that, our boil was done.  5 gallons went into the fermenter at 1.066 SG, yielding about 70% efficiency.

Did Batch Sparging save time?

No, it did not.  Two things prevented batch sparging from saving time over fly-sparging:

  1. more wort, lower gravity: fly sparging seems to result in a more concentrated wort, which means we can start the boil right away.  Batch sparging seems to yield more wort at a lower gravity, which means we have to spend 30 – 40 minutes boiling off water before we can start adding hops.
  2. rest between batches: batch sparging guides usually say to wait between batches and let the water leach more sugars out of the grain.  That takes an additional 20 minutes.

So besides the time spent draining the mash tun (15 minutes) you add another hour for resting and boil-off, and batch sparging doesn’t save us any time.  But it was a bit easier, and we didn’t have to monitor the gravity near the end of the sparge to avoid tannin extraction.

Into the Secondary

We’re somewhat slow writing up each brew, so this IPA is already being dry-hopped in secondary.  You see, we’ve got a friendly competition coming up where this IPA will be pitted against 15 commercial hoppy beers, so we’re under the gun.  Final gravity into secondary was 1.016 SG for an ABV of 6.5%, which was right on target.  We’d planned to dry-hop with Willamette and Ahtanum, but after trying valiantly to drink an Ahtanum dry-hopped Kolsch at a local brewery, we sprinted away from this combination.  Luckily our freezer had a half-ounce each of Simcoe and Amarillo, both excellent IPA dry-hops.

When it’s done, we’ll do a proper tasting and give you all the details.