Friday 26 August 2016

Kohatu Session IPA

Nearing the end of my pre-summer brewing step-up (meanwhile, summer is just about over - typical), I decided to brew another beer in my one-hop Session IPA series. While it hadn't been that long since my last one (in March, an all-Nelson Sauvin beer), this is a style - and experiment - that I really enjoy brewing, and even though I've done five different beers in this group already, I have plenty of other hop varieties that I want to try in it.

One of these hops is Kohatu, a variety I've never used in a beer before. Originating in New Zealand, I split a pound of pellets with a friend last fall, pretty much always with the intention of using it in a single-hop beer. Described on the Bear-Flavored Ultimate Guide to Hop Varieties (I use this all the time; thanks Derek!) as having "intense floral characters, grapefruit, pine needles, and tropical fruit", it sounded pretty good to me; kind of like a mash of Chinook and Simcoe, with another fruity Southern Hemisphere variety thrown in. Summer is the perfect time for low-ABV beers with these characteristics, no? Ok, any time of year is good for these beers, really.

Apparently Kohatu is a descendent of Hallertau Mittelfruh; it's been available commercially for the last few years or so. It seems to range in the 5-7% AA zone; digging around a bit more online, I was getting the impression that opinions vary on just how "intense" its characteristics are. That shouldn't surprise me, really, but more brewers than not described is as less punchy than hops like Citra, Nelson Sauvin, Azacca, etc. etc., so I kept this in mind when planning the recipe.

Partially because I was lazy, but mostly because the Nelson Sauvin Session IPA turned out so tasty, I used the exact same grist as last time. This is actually the grist for the very-popular Russian River Row 2, Hill 56 clone that has been circulating for some time (my attempt at that beer is here); for most of my Session IPAs, I had fine-tuned a recipe of my own, but with the Nelson one I decided to go with this grist, and was happy with it for that beer. The key is to aim for a mash temp of 153-155 F, so that you can help boost the body a bit.

Also with the other Session IPAs, I had come up with a hopping schedule I felt worked well: a little bit of Polaris or hop extract at the beginning of the boil, then one ounce of whatever hop was featured at 10 min, a two ounce addition at flameout for a 15-minute hop steep/whirlpool, and a three ounce dry hop. This time, however, I bumped up the last two additions - I had 8 oz total of Kohatu, so I decided to just use all of it in this batch. Therefore, three oz at flameout, and four for the dry hop.

Once again, as in the Nelson Sauvin Session IPA, I decided to ferment this batch with London Ale III. While all of the others used US-05, I was really happy with how the LAIII worked in the last batch - fruity, juicy, great mouthfeel, and of course, hazy! I also tinkered with the water chemistry, aiming for the "more chloride than sulfate" approach, which I've had good results with.

The brew day went normal, no issues, and fermentation was going strong around 24 hours after pitching the yeast slurry. I kegged the beer a couple of weeks after brewing it, and was drinking it a few days later. I was a little unsure how I felt about it at first, but after settling into its own after several days, I started enjoying it. Is it my favourite one-hop Session IPA I've brewed? No, but it's not my least favourite, either. Kohatu definitely has some of the characteristics mentioned above - it definitely has a light tropical fruit note in the flavour, and a light amount of pine as well. There's also this light spicy character that is pretty interesting, and works well with the other flavours and aromas. I think you could describe Kohatu as complex, if not intense... does that make sense?

As you can see, the key word here is "light"; I definitely would consider Kohatu to be less-punchy than some other varieties. Based on my experience, in the Southern Hemisphere hop category, I'd put it somewhere between Summer and Nelson Sauvin. So, it works well on its own, but may be better put to use with at least one other hop to bolster it a bit. Mind you, this is the only time I've brewed with it, so take my thoughts with a grain of salt (actually, I urge you to always do that!). Either way, a hop variety that I would gladly use again, and a tasty beer that ended up being perfect for summer.

Recipe Targets: (5.5 gallons, 80% efficiency) OG 1.048, FG ~1.013, IBU ~34, SRM 4.5, ABV ~4.5%

2.3 kg (57.1%) Bohemian Pilsner
1.35 kg (33.5%) Maris Otter
160 g (4%) CaraRed (20 L)
120 g (3%) Carapils
100 g (2.5%) Acid malt

Polaris - 6 g (20% AA) @ 60 min
Kohatu - 28 g (6.4% AA) @ 10 min

Kohatu - 84 g @ 0 min (with a 15 min hop steep)

Kohatu - 112 g dry-hop for 5 days (in primary)

Misc: 1/2 tab Irish Moss at 5 min

Yeast: Wyeast 1318 London Ale III (with a starter, ~175 billion cells)

Water: Fredericton city water, carbon-filtered; 5 g Gypsum and 8 g calcium chloride added to mash

- Brewed on June 13th, 2016, by myself. 50-minute mash with 13 L of strike water; mash temp on target of 153 F. Mashed-out for 10 minutes with 5.5 L of boiling water to 165 F. Sparged with ~4 gallons of 168 F water for final volume of ~6.75 gallons.

- Pre-boil gravity at 1.040 (target 1.039). 60-minute boil. Final volume ~5.5 gallons; OG a bit high at 1.049. Chilled to 64 F, then poured into Better Bottle. Aerated with 60 seconds of pure O2, pitched yeast at 64 F.

- Plenty of activity by the next morning, reaching its peak that evening with a temp of 70 F. Started slowing down after a couple of days - but the krausen remained thick and milkshake-like even a week later (pretty common for LAIII).

22/6/16 - Added dry hops into primary; FG 1.011. Racked to keg five days later and started force carbing.

Appearance: Pours with a moderate-sized, white head with fairly good retention - fades to 1/4 finger or so after a couple of minutes. Body is light golden, with a decent amount of haziness.

Aroma: I wish I could describe it better, but it's kind of a mix of fruit (grapefruit as advertised) and spice, and slightly floral. Surprisingly has quite a lot going on, even if it's not what you would describe as "punchy".

Taste: Mainly a light fruity character accompanied by light spice. This isn't the phenolic spiciness that you see with Belgian yeast, it's something different. Luckily it's mild - it doesn't taste like someone raided the spice cabinet and dumped it in the beer. Medium-light bitterness in the finish.

Mouthfeel: Medium carbonation, medium-light bodied; smooth.

Overall: A tasty beer, and an interesting hop. I'm curious to what it would be like used with some other variety(ies); depending on what else you added, would the Kohatu be drowned out, or complement the other? Something I'd buy again in the future to experiment with more!