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Mango Dairy Jaws (Part Two)

Written by Rob Hern

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Posted on September 16 2017

Alright, we’re back at it for Part 2. If you haven’t read Part 1 yet, here’s what you missed: NEIPA style guidelines and the brewing process for a Milkshake IPA. In this follow-up post, I’ll be focusing on what happens after brew day. Let’s get into it.

DRY HOPPING

When I first heard about the practice of dry hopping during primary fermentation, I wasn’t buying it. I have played around with it a bunch, though, and based on my own sensory I do think that it has an effect on the final beer. This could have a lot to do with just the sheer amount of hops that are used, but the main reason for the primary fermentation dry hop is biotransformation. The chemical reaction that occurs as our wort is transformed into beer can affect the end flavour of the hops we add in. We whirlpool hops to avoid full isomerization when we are looking to infuse aroma and flavour into the beer, but the high temperatures can still be a volatile environment for the aroma we are trying to maintain.

With traditional dry hopping, fermentation is in its secondary phase and so there is no chemical reaction going on to infuse the aroma and flavour into the beer. Instead, we are infusing the beer by steeping large quantities of hops. The addition of primary fermentation dry hopping impacts the finished beer in a few different ways from traditional dry hopping. If you were at the talk at TWB, these are all the words that I couldn’t pronounce properly. When we dry hop in primary the biotransformation gives us increased access to existing essential oils and compounds.

Terpenes – volatile unsaturated hydrocarbons that are found in the essential oil of plants (Hops!). Monoterpenes are in contact with the yeast during fermentation and react with the hops that we add in and, in turn, promote the fruity tropical notes that we’re looking for.

Glycosides – the release of non-volatile aromas (in our case sugars) during fermentation. Glycosides in their original form are said to be non-odorous, but when we change the environment the hops are in - boiling, whirlpooling, biotransformation - we then gain access to the odours. One scholarly report stated that it is considered the core aroma associated with hops in beer.

Thiols – fruity, sulfur-based compounds that are released and increase citrus, tropical fruit, onion and BO aromas in hops. Thiols are already present in hops and we do access them, but the addition of primary fermentation is supposed to grant us greater access.

Full disclosure: most of the information I could find online on this topic was directly linked to cannabis, not to beer. I was able to find a few scholarly journals on the subject of different types of terpenes and the role of glycosides, but to try and sum that up is a short book in itself. I was slightly frustrated while trying to dig up more information on this with regards to biotransformation as it was not often mentioned, but from what I can tell it is still a very new technique and there does not seem to be a lot of information published about it directly (at least not that is available to me at this time). There is a lot of random info on homebrew forums, which is a great start, but I was looking for a little more scientific research and was not overly successful.

OTHER ADDITIONS TO CONSIDER

Vanilla beans are very common, but I didn't use them.

Oat Milk – hey, if you are lactose intolerant, go for it! It’s a great alternative.

Fruits – lots of options here, but tropical fruits and berries seem to be the go-to. We pureed fresh mango at a rate of over a 1lb per gallon and people at the event said there could be more mango present in the mango version. When considering your fruit addition, pay close attention to your hop additions and try to have them working together in the flavours you are looking for. You can go fresh, frozen, commercial puree, or natural extracts. Each one comes with its own flavour attributes and there is not necessarily a wrong choice.

Whenever I talk about fruit, someone inevitably asks about additional alcohol points and how you calculate for it. To be honest, I don’t do it very often. As far as I am concerned, it is not a huge factor but, if you are trying to reproduce things exactly, I get it. Blend in your fruit and make sure it is properly mixed into the beer, then take a sample and measure it. Let it kick in another fermentation on the fruit sugars you have added and once it is done take another reading. Now calculate the ABV created and at it on.

It is always worth noting that the fruit you use - especially fresh - will vary from year to year. Each harvest will be different. Keep in mind that how ripe the fruit is will also significantly impact the end results. Some of the mangos we used for Dairy Jaws were not as ripe as I would have liked, which was part of the motivation to puree it all. I think this was a factor in people asking for more mango in the event version of the brew.

In the end, I blended the dry hopped and fruited versions for myself down at the shop and think the resulting beer is the best option of the three. One of my main complaints with this style is that a lot of commercial examples have no balance and in no way resemble an IPA. When putting Dairy Jaws together I wasn’t looking for booster juice in pint form. Some people love the fruit punch/booster juice style milkshake, but it’s just not my thing and I feel like it does a disservice to the base style. Something to keep in mind while you stomach the price of the hop bill. If in the end, you can only taste blackberries…. well, you see where I’m going with this.

One thing that came up at the Homebrew Hangout that I didn’t mention in the talk was the use of apple puree as a base addition for your milkshake. I didn’t dig too deep on this side, but a few professional breweries are said to be doing with Omnipollo being one of them. This was not done with Dairy Jaws, but I imagine it would work well and potentially could be a much more affordable way to increase that fruit note – apples are way cheaper than mangos!

EQUIPMENT CONSIDERATIONS

So much fucking hops and mango puree, and you need to have a way to leave them behind. Cold crashing is great, and you could also use a fining agent. I rarely do. I ferment in 15G keg fermenters and on each fermenter I have keg dip tube screens. This time around, they weren’t up to the job. I have recently brought in hop infusers for the shop. I have drilled a hole in one of them to drop the draw tube into and see if this larger screen will help with clogging. In the end, I could transfer the double dry hopped version under pressure but I was unable to transfer the mango version this way. Everything was just constantly getting clogged. I ended having to go old school and use an auto siphon. The main issue with this is that it opens the beer up to oxygen, which as we all know is the enemy at this point in the game. Whenever I do a dry hop, I purge with CO2 first and then 3 times after once the lid is closed. When I had to use the auto-siphon I was constantly blowing CO2 into the fermenter to try and keep a blanket on the beer even though the top was open.

Finally, I should mention that Culum and I brewed about 120L of Dairy Jaws. Because of all the fruit and hop additions, loss was almost 20L. Just something to keep in mind - you will not be able to get every drop out of your fermenter unless you want chunks.

Alright, we made it to the end! Any questions? Write them in the comments section below, and I’ll get back to you asap. Otherwise, happy brewing.

Cheers,
Rob

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