Kilning and flavour development

I came across this really interesting graph while looking for information on kilning and diastatic power. It’s from a presentation titled “Unraveling the Malt Puzzle” by Joseph Hertich and the Michigan Brewer’s Guild. It shows the importance of moisture content and kilning temperature on flavour development, specifically stating that the 145-155F 62C-68C range at 25-35% moisture content is the most optimal for flavour development. This is new to me, so far everything I’ve read about kilning pale malt states that the temperature shouldn’t be raised above 50C until the moisture content is below 10% I think I’ll give this a try.

 

New malt kiln

Still on the quest for a more authentic diastatic brown malt. I was pretty disappointed with the soot that appeared on my last batch and I wanted to play around with using higher temperatures so a new kiln was in order. Unfortunately I live in a townhouse, otherwise I would have built one by now using cinder blocks or anything I could get my hands on. Instead I had to settle for something on a more portable scale. I had originally thought of using a barrel so that I could take it to a campsite close by and put it over a fire pit, that way I could try using straw as a fuel. Then I figured why not use the gassifiers in the barrel, it’s clean, very safe, and I get one hour of burn time for each load of pellets. Every time I try burning straw it burns faster than paper, I still don’t get how this was used in the early malt kilns.

As I mention in the video I just didn’t have the time to perfect the design and my malt was at 10% moisture level after air drying for two days, it was more than ready to be kilned. The temperature crept up to 250 by the end of the first hour, there was still steam coming off at this point. During the second hour the temperature rose to 275 and then to 300 during the third. I knew this would probably be too hot for the malt to have any diastatic power left to convert itself but I wanted to see how a faster and hotter kilning would affect the colour.  My results were most likely inaccurate because even though my oven thermometer read these temperatures the heat coming out of the small holes in the barrel was much higher. The 4 oz. test batch came up with a 1.020 original gravity after an 8 hour mash.

Well at least now I know I can make a pretty descent blown malt, check out the snapping action in the video. As well this would be a great way to roast your grain outside, you could easily do 7 pounds at a time this way.

 

Put this on your christmas list!

Last Thursday night I got to go to a presentation by renowned beer historian Ron Pattinson who was in Vancouver promoting his book The Homebrewers Guide to Vintage Beer. Chances are if you’re reading my blog you’re interested in all things beer and already know who Ron Pattinson is. If you don’t, get the heck off my blog right now!  Go to Shut Up About Barclay Perkins for some serious reading – then come back to my blog. The event was organized by Vanbrewers and took place at the Cobalt on Main street. The focus of the talk and the book was on historical english beers and many of the facts were quite surprising to me. I had no idea that English brewers used invert sugar to such an extent and often used caramel to adjust colour. He also eplained that the purpose of the parti-gyle method of brewing was for efficiency and to allow the brewers to be able to blend the different worts in order to acheive a consistent starting gravity for every brew. Another surprising fact was the use of attemperators (which sound like large scale immersion chillers) to control the temperature of fermenting beer during the 18th century. The book is full of recipes from 1804 to 1955 based on the actual brewing records of the breweries and are all scaled down for home brewers. I can’t wait to try some of them! Of course I got him to sign my copy – it says “Hope you make nice porters with your diastatic brown malt” How cool is that?

 

Diastatic Brown Malt 2014

 

 

Last year, after my first attempts at making diastatic brown malt I realized that I had just scratched the surface of a vast subject but that it was definitely worth further experimentation. The beer I made was very unique but very light in colour. This year I thought I’d collect some useful data by pulling out 1/2 lb samples from my “kiln” at 1/2 hour intervals starting from the 3 hour mark, which is where I stopped last year. I kilned for 6 1/2 hours before running out of malt. My final conclusion – I could still go darker! To do this I think I could increase the heat of the fire to 300 F (but that’s for the next batch). The picture above shows from left to right: My pale malt, 3 hour brown malt, 3 1/2 hr., 4 1/2 hr., 5 1/2 hr., then 6 1/2 hr. The 61/2 looks lighter because it’s cloudy. Check out the jump in colour from 4 1/2 to 5 1/2. It was around the 5 hour mark that the temperature rose to 300F. Just to clarify these times are the curing times. I had air-dried this malt for about 36 hours and then kilned it for 5 hours with one gassifier no higher than 150F.

6 1/2 hour malt

The colour of the malt did not change as fast or as much as I thought it would but I’m very excited about the 6 1/2 hour malt. Despite looking quite charred in places it did have some diastatic power left in it, enough to give me a potential O.G. of 1.028. In comparison the 3 1/2 hour malt, (under the same brewing conditions and volume) would be 1.051.  I was scaling down to 500ml as a final volume and constantly switching from gallons to litres and back again so I’m sure the math went a little sideways. Since I’m just comparing the samples I figured it wasn’t too important as long as I mashed each 4 oz. sample the same way.

“Dad what are you making? it smells like chocolate!” – my 8 year old daughter while I was boiling a decoction from the 5 1/2 hour malt. And I would agree with her, it’s an awesome smell, much less smoke than last year perhaps due to the oak pellets. I think a beer made from one of these is going to be amazing.

These mashes were very long. They started at 152 degrees and after three hours the temperature usually dropped to about 135. I did a decoction every three hours to bring the heat back up to 152. I would use my refractometer to see what kind of progress I was making and I was really surprised to see the brix rise steadily with the darker malts even though they didn’t fully convert. Interestingly, nothing changed after the 8 hour mark for the 6 and 6 1/2 hour malt even though I mashed them for 10 hours.

HEALTH WARNING : I have to point this out because it’s a little worrisome. The 5 1/2, 6, and 6 1/2 hour malts look rather sooty. They’re grayish in colour and when I handled them the soot seemed to be coming off on my hands. I could be making something highly carcinogenic. This could be because one of the gassifiers went out and smouldered a while or it could be that my offset smoker system is just too small and as the flames hit the top of the firebox soot accumulated on the grain. Since my latest results are showing that I don’t have to be as careful with the temperature as I thought I might make a better system with the flames directly under the malt. Perhaps in an metal drum or something similar. Because of this sootiness I would not recommend using an offset smoker, I don’t want to be responsible for anybody getting cancer!

 

Note: The Pale malt is from a different batch of malt but I included it to compare conversion times. Probably could have gotten a better SG had I adjusted the pH properly. Also I did not include the 3 hr malt as I thought it was unnecessary.