It’s been clearing out at 2,5 °C for over 24 hours already, so I couldn’t wait any longer and took a little sampling. And it’s a-lovely :D
This is pretty much a classic stout, but with Viking Malt’s Sahti malt for the majority of the grist. The void-ness comes from Viking Malt’s Black malt (1300 - 1500 EBC). Some leftovers of Tuoppi caramel rye malt and a calculated dose of Simpson’s Premium English caramalt also went in. The rye in particular is keen to hijack the taste profile, bringing in the taste of Finnish classic ‘kotikalja’, a non-fermented malt beverage. That one is kept in it’s place, but I do regret not using a bit more of the English caramalt.
The yeast used was the fresh yeast that’s a hallmark of the sahti style. It gives a banana-like flavour, and I’ve found it can be controlled to a great extent by adjusting fermentation temperature. This one was set to 16,5 °C. Around 14 °C the banana aroma tends to get overpowered by fruity hops. Pressurised fermentation at 0,8 bar as always.
I made this batch to use up some leftovers, so I went with a pretty daring dosing of Moutere hop pellets for the first hop addition, followed up towards the end of the boil with Challenger. On this first tasting the Moutere is surprisingly subdued.
Plenty of time to run some xmas bottles for friends and family :) Cheers!
Well, I don’t measure it :) I’m only able to make ~21 L so I’d rather not lose the amount that would float the meter. Seriously considering investing in a refractometer that only takes a drop or two.
There’s 4,6 kg of active malt and 1 dl of dark syrup in the yeast starter and I ferment to the bitter end, so I’ll wager it’s in the 7 % ballpark. Sahti ought to have a lot of sweetness because the fermentation is incomplete, so the caramel malt is there to compensate.
Refractometers are no good at all, especially with THIS much colored stuff. Could get over 2x error, which is nonsense.
After all, you don’t have to lose that stuff, if you had a tall and narrow plastic cylinder, that would fill that glass on the photo when you are done.
I was thinking to design and build a U-tube density meter for regular people who can’t realistically spend a few thousands on proper tool, I can see those in slightly above decent refractometer price range (and that would indeed take small amount of sample, not as small as refractometer, but still). I wonder if I’d be able to sell enough to cover the expences (and myself I do have a ridiculously expensive and unnecessarily fancy MettlerToledo U tool in addition to all floaters and refractomters, remaining from good old times I was hoping to do paid analytics for microbreweries and thus needed something certified).
I’ll have to take a look at the U-tube concept, I might beat you to market :D
I already have found a glass vase that’s ideal size for the floater that I have, but I’m concerned the tight tolerance of the float against the wall would also produce an error. And it still would take a good 0,2 liters to use. Sure enough, the finished product can just be enjoyed (actually only quite recently I realised that the FG sample can be quaffed :D ) but the OG sample will certainly not go back into the wort, and being T1D I shun sugary treats :P
Good to know refractometers are not useful in the Dark Arts :D Brew shops do sell them though.
Refractometers are quite useful for pale wort and clear distillation products - or anything where you calibrate close to target phase subspace (honey, must, well-known beer recipe, etc.). I use mine to determine when fermentation rate slows down to determine termination in yeast tests - their relative readings are OK, if they aren’t changing, it’s worth considering density is stable.
Regarding U-tube, that’s fun enough little project if done right. I had even more daring idea to build contactless (read through glass) density scanner, I even have the already soldered and flashed board and transceivers somewhere around the place. The prospect of quick reading density and inner fluid temperature without exposure seems attractive enough, but it’s a lot of research work to tune this tool concept, and then to turn it into comfortable product, and I’m kind of short of time-money invariant resource now.
Wow, your sandbox sure does sound like an exciting place! I hope life plays out so that you have the temporal resources to devote to such endeavours.
Is it just the permeability of light (struggling with English here :) that needs to match – I mean if one was to make a series of standards with a base of some dark food colour, maybe something to slightly nudge up the density of the base, and of course known amounts of ethanol in a sane range, maybe that would make a refractometer useful here?
I’d imagine something like that has already been thought out for red wine. Must. Research.
Thank you for the inspiring thread :)
Ok, so if you are interested in measuring methods for density:
gravimetry - you weigh your sample in standard vessel (you have to have constant temperature)
the floaters (hydrometer) - you read the line on the scale.
the U tube - it measures resonant frequency when it is vibrated. The frequency is dependent on density of the tube + sample.
optical methods- these indirectly measure something in the sample, in our case it is sugar.
So you have to ask yourself what you measure. With methods 1-3 it is gravity, with methods 4 it is something different which points you to some approximation of gravity. Also I am long from school so my terminology might be mixed up.
Cheers, that’s a nice primer. I do have an engineering degree that covered plenty of analytic chemistry :)
I’m only concerned with taking OG and FG with as tiny a sample as possible = creative pycnometry or getting a refractometer. Although just today I realised a pendulum might also offer a creative gravimetric insight…
Craft brewing, baybee XD
There is AntonPaar EasyDens which is used in small brewerys here. Still not ideal for homebrewing at 500€, it is more for commercial use price range.
I think that they have to be built to withstand some abuse. The U tube is prone to get dirty and throw off the measurements over time.
Why would you lose anything? You can pour it straight from the test tube down your throat… And it really only takes like 50ml to begin with.
Sounds like there are more compact floaters to be found… …I’ve picked up a vase that just fits my float and that would take 200 ml if not more.
Personally I haven’t been that bothered with measuring my efficiency, but my old dad keeps pestering me to get some measurements done so he can finally decide if my stuff is ‘better’ (= stronger) than store bought :D
Haha I’ve only got a test set when I was making gin, since the raw alcohol has above 70° abv after distilling, so I needed to dilute it down with water to about 38-42° drinking strength, so had to be fairly accurate. Now I’m using the kit habitually for any brew.