Matress Down the Stairs NZ Pils

First brewday in 8 months, and the goal of this brew day is an NZ Pils. Going for slightly more German than Czech Pilsner, with a good whop of NZ hops aroma, a decent Pils bitterness, and a subtle yet strong malt backbone over a nice crisp clean beer. We'll see if it gets there.

This is a warm fermented lager brewed under pressure, at temperatures a bit warmer than I was anticipating - ended up being around 21-23C (69-73F) most of the time. Most of the stuff I could find about brewing lagers under pressure talks about fermeting at ale yeast temperatures, around 18C. I did brewed this at about 15PSI, using a Fermentasaurus with a spunding valve. 

Here's the recipe:

Numbers

• IBU 42
• Target start SG 1.048, Measured 1.042 (seems my efficiency isn't quite what I thought it was)
• Target final SG 1.012, Measured 1.004
• Target colour: 3L (which is probably light, those photos up there make it look a bit more amber than it was... it looked a bit sickly pale to be honest)
• Target ABV 4.7%, Calculated 5.0%

Setup

I have a home made one vessel set up, do the mash and boil in this guy (which is the boiler from a Turbo 500) with a ball valve tap, a bazooka screen and a thermometer attached. Also a plate heat exchange chiller ($70 NZD from FengCi Eng on Ali Express) with a very dodgy home wired pump that I got for about $3 on ebay from China several years ago. I also use two 15L pots I got from Kmart - drain the wort into one and sparge using the other, then drain the sparge into the second. I turf out the grains (well I actually kept them and made some food with them) and then tip the wort back into the boiler to boil.

Ingredients

All NZ ingredients, other than the yeast (which I'm led to believe is derived from the Pilsner Urquell strain). 

• Gladfield German Pilsner Malt - 4kg (89%)
• Gladfield Gladiator Malt - 500g (11%) (equivalent of a cara-pils)
• Waimea Pellet Hops - 100g (10g first wort hop 60min boil / 20g  5 min boil / 50g whirlpool at flameout)
• Riwaka Pellet Hops - 100g (100g whirlpool @ 80 degrees)
• White Labs WLP800 Pilsner Yeast (starter 3 days prior)
• Palmerston North tap water

Yeast Starter

• 1.5L starter with 200mg Light DME
• Measured SG 1.042w
• Siphoned off clear stuff prior to pitching

Mash

• Thickness - 3L/kg (13.5L water, 4.5kg grain)
• Schedule - 1 hour, 66C (151F) single infusion mash (72C [162F] strike temperature) - ended up sitting more about 67-68C.
• Recirculate 10 mins, Drain 9L (first wort hop 10g Waimea - pictured below)
• Sparge 10L (at 77 degrees) x2 (=29L minus equipment loss)
• Aim SG 1.048

 

Boil

• One hour boil (no further hops added at this stage)
• 20g Waimea at 50 mins (i.e. In boil for 10 mins)
• 50g Waimea and 100g Riwaka with 30 minute whirlpool / chill
• Waimea 50g at 90 degrees - 10 min rest
• Riwaka 100g at 70 degrees - 10 min rest

Fermentation

Cooled to 21C before pitching the yeast. The 500mL collection bottle at the bottom of the cone had was full of trub within a few hours, which I turfed, and then didn't need to discard any more. It reached 15PSI within 24 hours, and I kept the pressure at that for the remainder of the fermentation. I love the clear wall of the Fermentasaurus, which allows you to really see the yeast activity and the change from a turbid wort slurry to a nice looking beer.

 

As I mentioned above, we had a beatiful NZ Christmas, but unfortunately a bit hot for the fermentation, so this sat at about 21-23C for most of the time, with a little bit of diurnal variation as the nights were cooler and the days were hot and humid. I couldn't find anything anywhere about brewing a lager under pressure at this high a temperature, so I wasn't really sure what to expect.

I took a reading on day 8, and SG was 1.004, lower than anticipated, giving an ABV of 5.0%. I also (naturally) took a half a glass to taste at this point (it was already carbonated from the pressure brew, so I just stuck it in the freezer for ten minutes to cool it down). More bitter than I expected, but probably not unreasonable for a Pilsner, the hops aroma was far more subdued that I wanted. The beer was very cloudy and therefore not particuarly crisp like a lager, but I was hopeful 

that would change with a cold crash and a few weeks of lagering in the keg. But the most impressive thing was that even with such a warm fermentation the yeast flavour was very minimal (maybe the slightest hint of banana, probably less so than a Heineken). Early days, but overall I was hopeful at this stage.

Transferred to the keg under pressure (filled the empty keg with CO2 at 10 PSI, connected the spunding valve set at 10, then connected the gas tank to the fermenter at 15PSI and connected the fermenter (with the ball float) to the keg (which also had a ball float). 18L transferred, and put most of the last (very sludgy) litre into a bottle to bottle condition. Let the pressure out and when it stopped bubbling, harvested the yeast from the collection bottle.

After a week in the keg I did a little taster. Overall quite disappointed with the lack of clarity and lack of hops aroma. There is a slight yeastiness to the beer that fits with being fermented too warm, but it's reasonably subtle. Nice pilsnery bitterness, nice body and overall pleasant to drink, but unfortunately well below expectations. Wife check passed though, she thought it tasted pretty good at this point.

Another three weeks in the keg (the keg is probably close to half empty by now I must admit), and the flavour continues to improve. The clarity has improved a little, but it's still far from clear, which as far as I'm concerned is really a critical fail for a Pilsner. The harsh bitterness has died down to a beautiful Pilsner bitterness, but there is still very little aroma, especially considering 100g of Riwaka at flame out! The yeastiness is still a present but subtle, but I think actually adds to the beer rather than detering from it. Overall, I'd call this beer a fail for achieving what I set out to achieve, but it's very drinkable and I am quite enjoying it. I'd call it an unintentionally hazy NZ lager rather than a Pils, but if that's what I'd aimed for it's not too bad.

Addition: I was probably a bit hasty and impatient... A few more weeks down the track (see the first picture up top) the beer has become quite a bit clearer, and more importantly the flavour has improved, it really does come together quite nicely now and tastes like a Pilsner, albeit not quite as Hoppy as I would've liked. Gets better each time I drink it, pity it's run out. Another lesson learnt: patience.

The good:

- Fermenting WLP800 under pressure (15 PSI) at 21C (70F) seems to produce quite drinkable beer without any real off flavours

- Nice hoppy bitterness from the Waimea

- Malt flavour is presnt but subtle, good body and head retention, just how I'd aimed really

The bad:

- Real lack of clarity, probably too much hops, probably could improve my whirlpool technique, perhaps should try using some Irish Moss or finings (I never have used these, and had always wanted to steer clear... but...) - I wonder if fermenting the beer too warm contributed to this at all...?

- Real lack of hops Aroma. Not sure why given the big whack of Riwaka at flame out, perhaps the beer was too cold when I added them, perhaps I didn't leave them in long enough before cooling, perhaps they'd have been been better as dry hops (or not at all) but I definitely couldn't taste them. The wort smelt way nicer than the final beer does! The final beer is pictured up top.

I've decided I will re-attempt another iteration with the following changes:

- Substitute the hops for a dual purpose hop, put far less in the boil and perhaps even use some for a dry hop (I'm thinking Motueka, and maybe cones instead of pellets)

- Add Irish Moss at the end of the boil

- Try and improve the whirlpool and maybe recirculate the wort a little longer