Overview of my current techniques and thoughts about other approaches
Adding enzyme on the hotside is my personal preference for a few reasons that result from being able to denature the enzyme in the boil. Firstly, adding enzyme to fermentation seems to affect the hop aromas. I was initially making these beers with around 4 pounds / bbl (about 15.5 g / L for you metric people) and the aromas and flavors were much more mellow than expected. There were also some qualities to the hop profile that, to me, were reminiscent of leaving a glass of highly hopped beer out long enough to warm up and get a little mushroomy or stale tasting. Not a skunky light struck flavor, but something else I find in this situation. Another problem to enzyme in the fermentation is that the enzyme seems to always be finding things to turn into glucose so the fermentation piddles on indefinitely and eventually needs to be cut off. A common problem with many Bruts is that they possess flavors of incomplete fermentation such as diacetyl and acetaldehyde. For all these reasons I don’t use Amylo on the coldside any longer.
The two hotside methods I’ve experimented with involve adding Amylo to the mash and adding Amylo to the kettle during lauter. I’ll guide you through both of my techniques and discuss my successes.
One thing I really stress is that there is still a lot to explore. I’ve drunk some fantastic Bruts that used enzyme in the fermentation. I’m aware that some larger, more scientifically able breweries are trying to make Brut IPA without the use of enzyme at all. Their approach involves mashing techniques and various types of base malt that is extra high in diastatic power (distiller’s malt?) and who knows what else. Super attenuating yeast is a possibility (though the ester profile should be nuetral to make a “classic” Brut IPA). Other enzymes and enzyme combinations are also certainly worth exploring. There’s enough options to make me wish I had 10 fermenters, a real science lab, and all the equipment necessary to try as much out as possible. I, however, have two fermenters dedicated to ale production, very minimal lab equipment, and brewery equipment circa 1996 that will not be upgraded any time soon. This is why I love to talk about Brut with as many other brewers as possible to see what they’re up to.
I’m hoping that my two current methods can provide some guidance, but as Levar Burton always said on Reading Rainbow, “you don’t have to take my word for it.”
This is the method I’ve used the most. My results have been tasty, but not quite as dry as I’m targeting. I’m achieving a finishing gravity of 0.7 Plato at best, but would like to be around 0.5 Plato. The beers are plenty dry to distinguish themselves from a dry West Coast IPA, but I’d still like to push it a little bit further. I know other breweries that are getting all the way down to zero using the same dosage rates as me. What are they doing differently? I’m not exactly sure, but it’s most likely just better mash rakes and mixing than I’m able to achieve on my brew system.
I use Amyloglucosidase at a rate of about 1.25ml / pound of grain (3ml / kg of grain)
I mash as normal but shoot for a target mash temp between 145 and 149 F (about 62 to 65 C)
I take a temp reading about a 1/3 of the way into mashing to ensure I’m below the threshold for denaturing the enzyme (which I believe is a little above 150 F or 66 C, though I’ve read various things on this). At this point I add about 1/3 of the enzyme I’ll be using.
I add another 1/3 of the enzyme about 2/3 of the way into mashing and add the rest once I’m finished getting the grain into the mash tun.
My mash takes around 30 minutes from start to finish. With Bruts I leave my mash rakes on an extra 10 minutes and rest for a full hour before lautering to allow the enzyme more time to be in contact the grains.
I use cooler sparge water than normal, so that as I’m sparging the mash remains the same temp and the enzymes are still able to do their work. For me this means my sparge water is around 162 vs. my usual 168 F. I don’t do “mash outs” or any temperature raising on my system so normally, as I lauter, my mash raises temp a little bit but in this case, not at all.
Everything else is normal from here on out except, because our wort is very high in glucose content, it will be a different experience for our yeast and thus VERY important to use yeast nutrient in the boil AND during fermentation.
I’ve only used this method once, but it got the finishing gravity all the way 0.2 Plato, which is a great place to finish. My kettle takes a long time to come to a boil at Social, thus this method adds quite a bit of time to my brewday, so I was hoping to get away with the mash application. I will however, be trying this method again on the next Brut I make and expect it really is the best way on our system. One potential advantage to this method is you could heat the kettle up in such a way that the last “x” amount of extract could be collected after the enzyme is denatured, should you prefer a beer that finishes at 0.5 Plato vs 0.0 Plato or find other advantages to having a little bit of unaffected extract in your beer. I think there may be some.
I mash normal and shoot for a mash temp of 145 F to 150 F (62 C to 65 C). If you’re planning on starting with low gravity wort in the boil that would require liquoring down to avoid low gravity final runnings, consider starting your lauter with a little bit of cold water. I’ve done that before and was incorporating enzyme at around 137 F.
I add the enzyme a little into the lauter at a rate around 15 ml / bbl of wort (or 0.5 ml / L ). If you want to, add it all at once or a little here and there throughout the lauter. I don’t think it makes too much of a difference.
I wait to heat the kettle up until I’m ready to denature the enzyme. I lauter over the course of 90 to 100 minutes. In my first experiment my kettle was just reaching 150 F (66 C) as it was full. That resulted in a 0.2 Plato beer.
Same as the mash method: Everything else is normal from here on out except, because our wort is very high in glucose content, it will be a different experience for our yeast and thus VERY important to use yeast nutrient in the boil AND during fermentation