Spent Grain Mashed again for Yeast Starter

I brewed today, first day of spring break, and had 10lbs of spent grain at the end of the brew. After 4 hours I guess I hadn't had enough torture :cross: so I decided to do a little experiment.

Basically I just mashed the spent grains 5 pounds at a time, directly in water in a boil kettle, 4 gallons. I assumed that with 75% efficiency in the brew, that I would be able to extract some residual fermentables.

I mashed at (44 F) for an hour, and then poured the liquid/grain into another kettle through mesh filter. I then came to boil and let it go for an hour and a half, to boil off extra water and produce a higher gravity "second wort".

Cooled to (78 F) and pitched a smaller starter I had already going, White Labs Pacific Ale.

I didn't know what to expect, whether it would work or not but I have a small farm of yeast so it's worth it for me to try it. Science!

Either way, after cooling at pitching, here I am 2 hours later to say that I have fermentation!

Just wondered if anyone else has done this? Hope I'm not clogging up the forums with this thread, but all I could find with "spent grains and yeast starting" were recipes for breads and dog treats.


-Corey

Just a note- I mashed each of the 5 pounds of 'spent grains' with 1.25 gallons of water, then boiled and reduced to roughly 1.6 Liters (2 liter Erlenmeyer Flasks).

Yep it's a great idea there. If you're going to use in in a week or two, just run off the extra wort into a milk jug ande refrigerate. Boil before using in your stater. BTW, it sounds like you mashed the spent grains... not sure if I understand you, but you didn't need to do that.

I think many here do exactly what you did. I do it. If it's a bigger beer, I just make a second beer from the grains (this past wkend I made a 4gal wee heavy from the spent grains of a 10gal belgian quad).

I think you're going to get a lot of tannins, and off products, don't think it would taste good , but I could be wrong let me know how it turns out

I'm not worried about any tannins or off flavors, I just want to propagate yeast, and will clean them from there. Any fermented liquid will just be poured off the yeast cake and then the yeast will be washed.

@PassedPawn how do you produce the wort from the spent grains without the second mash? I kind of figured I could just sparge them to wash some more sugars off, but I thought I could try and extract a bit more with a new mash.

mulhaircorey said:

I'm not worried about any tannins or off flavors, I just want to propagate yeast, and will clean them from there. Any fermented liquid will just be poured off the yeast cake and then the yeast will be washed.

@PassedPawn how do you produce the wort from the spent grains without the second mash? I kind of figured I could just sparge them to wash some more sugars off, but I thought I could try and extract a bit more with a new mash.

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The only reason to mash is to allow the enzymes in the malt to mix with the non-soluble starch to make soluble, fermentable sugars. That all happens relatively quickly, no need to do a second mash. When I say mash, I'm talking about adding water to the malt at very specific temperatures.

Just running more water through the grains should get much more sugars out. As you do this, and as the gravity (and pH!) of the runnings drops, you do run the risk of extracting astringent tannins from the grain husks. So, you should not take runnings under about 1.010 (you can use a refractometer for this). Of course, for your yeast starters it doesn't matter.

To make a second beer, you need to start with a much bigger beer. Search for parti-gyle on this forum and you'll find lots of good info regarding this.

i was brewing yesterday and i took some wort from BK and added some from the 3rd sparge, i ended up with over 4L of 1.060 wort for starters, i think from now im going to double sparge with extra gal or so in the 2nd, top off my bk and collect rest for starters

Polboy said:

i was brewing yesterday and i took some wort from BK and added some from the 3rd sparge, i ended up with over 4L of 1.060 wort for starters, i think from now im going to double sparge with extra gal or so in the 2nd, top off my bk and collect rest for starters

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This is what I do. Then I freeze 1L batches. I have one thawing now..

yea mice is in the freezer too, 3x 0.7L bottles and 2l one ale pet bottles thats 1.5 gal of 1.040 starter

mulhaircorey said:

@PassedPawn how do you produce the wort from the spent grains without the second mash? I kind of figured I could just sparge them to wash some more sugars off, but I thought I could try and extract a bit more with a new mash.

Click to expand...

Mashing is just to convert the sugars, so after the initial mash that step is already done. Next time just sparge the grains a bit more to make your starter wort and save yourself a lot of time.

Glad to hear the next time I do this I can cut my time down, immensely, haha. Thanks for everyones input thus-far.

Hello! Hope you guys don't mind me reviving this very old thread, but I found it to be almost exactly what I was looking for and also raising some questions.

I am currently doing a series of beer-archaeological experiments trying to recreate an ancient Armenian beer mentioned by the Greek author Xenophon. The beer is described as containing spent grains and pulses (perhaps lentils), meaning that the malt etc. was not strained before fermentation like most of us would do nowadays. I thought that perhaps the reason for leaving the malts in during fermentation would be so that the grains left over after fermentation could be used as a type of yeast starter. This is also how sour dough bread is made (i.e. using some of the old dough). I tested this theory out and it seems to work extremely well with pre-packaged yeast; now I'm going to try if it also works when brewing with wild yeast.

The process I have in mind is slightly different from the process you describe in this thread.

a) you filter the spent grains out before fermentation rather than keeping them in
b) you add the spent grains to a starter you already have going

Therefore, I was wondering if you have any thoughts on the technique I am describing above. Whether you perhaps have any knowledge of it being used, either in modern times or in the past and if you have any thoughts on this theory more in general.

Much appreciated!

Kyle