unusual problem + brewing before thermometers question

[brewbrew]

Hello HBTers-
I'm posting because I had an unusual problem and a question that came out of it: my last batch (which was my first all-grain batch) failed to start fermenting, though I pitched a good amount of yeast and oxygenated my wort, etc. I couldn't figure it out until on a strange intuition I stuck my thermometer in some boiling water and it read 235 degrees-- I'm figuring that I never even got the grain hot enough to extract the sugars, even though the color, smell etc. all seemed fine.

So my question is, how did medieval monks (or the hundreds of generations before) brew beer without thermometers? I'm very interested in historical brewing techniques, and I'd love to know if anyone has any insight into how it was done, other than guesswork.

Thanks!

 

[dgr]

Decoction mashing. That's how they did it before thermometers. http://braukaiser.com/wiki/index.php?title=Decoction_Mashing

So you mashed at 128ish degrees? You didn't even gelatinize the starch. If you had, you would have had some conversion. Was your mash tun even steaming? Didn't you taste your wort? It should have tasted sweet. You can still taste it. How exactly did you determine that it didn't start fermentation and it isn't converted?

 

[freisste]

What was your OG? Like 1.010?

 

[wailingguitar]

I read that water for single infusion mashing would become still and "mirror-like" when it reached appropriate mash temps. That was one method used, basically just observing the water. My own observations suggest that there is some truth to this.

 

[JohnSand]

They probably judged by experience. If you look at old cookbooks, recipes don't include temps. They say bake on a "hot oven", "very hot oven", "slow oven" or "quick oven". Cops are trained to judge the speed of a moving car by eye, many can do it with accuracy of 1mph. When I bake I can tell if it done by the smell. Humans have very precise senses if we use them.

 

[Homercidal]

This is where the "rule of thumb" comes from. People used to measure the temperature of their hot liquor by dipping their finger or thumb in and seeing how hot it was. AS you can imagine, it was not a very reliable method, but then, neither was their beer...

Alright, fine. Don't believe me!

 

[kombat]

As dgr said, they did it with decoctions. They figured out that if you take 3 gallons of water and boil it, then mix in 1 gallon of room-temperature water (or whatever, the actual ratios are irrelevant for this example), they'd end up at just the right temperature to optimize conversion. Of course, it took time and a lot of trial and error for them to arrive at the right ratio to get the right temperature, but that's how they did it.

With decoction/step mashing, the variable was merely how much mash they removed, boiled, and added back to the mash tun. They learned that if they removed 18 quarts, boiled it, and returned it, it resulted in a dry beer (getting them to, say, alpha amylase rest), but if they did it with 22 quarts instead, the beer would have more body (they'd end up slightly higher, more in the beta amylase range).

Their recipes were written to reference volume of water/mash to boil, rather than temperatures, since they had no way of measuring temperature (other than knowing that boiling was 212° F). They simply manipulated the amount they removed and boiled to control the temperature of the main mash after mixing it back in.

 

[brewbrew]

Decoction! That makes so much sense. Thanks everyone for your answers. I gave it a taste, and it is a little bit sweet. The gravity is low but dropping. Evidently there is some fermentation going on, it's just not visible. I picked up a new thermometer, but I'm actually going to brew two small batches this weekend as my next experiment, one with all the modern conveniences, and one by decoction that will be a gruit actually--I foraged some and bought some gruit herbs, and I'm going to give it a shot. Plus today's bottling day for a partial grain IPA I've been dry-hopping, so I'll have something to drink in the meantime. I'm loving finding out more about how they brewed before even amateurs knew chemistry, so these have been some great responses. Thanks again!

 

[glick]

When you checked your OG how did you not notice that it was crazy low? I think your thermometer was only half of the problem!

 

[brewbrew]

For sure, glick. I'm coming to brewing beer from mostly making gin and country wines, so I haven't gotten in the habit of using chemistry and tools but am also not acclimated to what the right sensory measures are as well. I didn't take a gravity measurement until I thought something was wrong. I don't know about where you are, but here brewing is practically free ($1/lbs for grains, hops are free this time of year if you know where to look, or $5/lbs in stores) so there's a lot of leeway to experiment. Definitely though, I messed up on this batch in several ways.