Grain Caps

OK, well I feel like a dummy asking this question but when your fermenting on grain does anyone out there take off the grain cap or just let it fall and become the grain bed?

I have done about 60 ferments on-grain using 100% malted grain, unless I am doing a bourbon of course, and most of the time I have just let the grain cap form and then gradually sink and in general I have had decent ferments with OK yields, 4%, with low grain loads .2kg/l. This week I have been trying triticale and I haven't done a cereal mash on it with for example 80% triticale and 20% malted wheat. And it formed a grain cap and then when that dropped it choked out the ferment like @LocalGoat told me it would. And when I ran it there was nothing in the run.

I am working on my fermenting technique, checking brix, modifying for PH and adding the right levels of DAP and Yeast EC1118. I am just feeling a bit lost working with unmalted grains. Today I will be doing a cereal mash on the triticale and then fermenting off grain like @LocalGoat and @punkin said you should do. So maybe that will get me a lot better result.

So my questions are:

  1. Does anyone take off the grain cap after initial fermentation when it forms?
  2. Does anyone lauter after the grain cap has formed, and is this a good or a bad idea?
  3. Does anyone use an agitator or stirrer to keep the grains in suspension and improve on-grain fermentation?
  4. Is there a significant difference in yield for on grain as opposed to off grain fermentation?

Recently I did two identical washes of a straight malted wheat wash and one was off grain and the other on grain. I got slightly less yield on off grain but the taste was definitely a lot better on the on grain which did form the grain cap and bed. But this was the only direct comparison I have done in a while. But I am asking as there will be guys on this board with a lot more experience than me.

Comments

  • edited May 17

    @DonMateo said: Does anyone take off the grain cap after initial fermentation when it forms?

    No, sounds messy, and it's counterproductive.

    @DonMateo said: Does anyone lauter after the grain cap has formed, and is this a good or a bad idea?

    Also sounds messy, but I think it's much easier to lauter a corn mash post-fermentation. The viscosity is significantly lower. Counterproductive - there is potential alcohol in the grain solids. Especially if you are using glucoamylase, which can hydrolyze ungelatinized starch.

    @DonMateo said: Does anyone use an agitator or stirrer to keep the grains in suspension and improve on-grain fermentation?

    We do, but we don't run the mixer continuously. We might mix 2-3 times over the course of a grain fermentation. We do it to knock down the cap and to rouse yeast. Mixed fermentations finish quicker.

    @DonMateo said: Is there a significant difference in yield for on grain as opposed to off grain fermentation?

    Product yield/efficiency of on-grain fermentation is significantly higher. Like I said above, enzymes remaining active in the mash will continue to work on unconverted starches that might have made it through mashing. This is why product yield of enzyme-active grain-in processes is nearly 100%.

  • edited May 17

    @DonMateo said: This week I have been trying triticale and I haven't done a cereal mash on it with for example 80% triticale and 20% malted wheat. And it formed a grain cap and then when that dropped it choked out the ferment like @LocalGoat told me it would. And when I ran it there was nothing in the run.

    Choked a ferment? This doesn't make any sense, sorry.

    The reason there is a grain cap is because yeast will affix themselves to grain particles, create co2, and float the grain particle. In addition, Co2 bubbles being generated in the liquid wash itself will collect under the cap, keeping it elevated. Only when fermentation nears completion, will there no longer be enough CO2 to elevate the cap, and it will fall. A thick cap is a symptom of vigorous, active fermentation.

    If you had nothing in the run, it's because you did not gelatinize the starch and convert it to sugar, or you got very poor/incomplete conversion (made a lot of dextrin). It has nothing to do with a cap, or no cap, or presence of residual grain solids in the fermentation.

  • If you like European whiskies, you'll probably like off-grain flavor profiles better, if you like American whiskies, you'll probably like on-grain flavor profiles better,.

  • I'm fermenting in my mash tun and agitate a couple of times manually during fermentation. Lauter to boiler, distill. IMO adds tons of flavor. Can't distill on grain as I'm having exposed element.

  • This is what I have been doing. Unmalted triticale confused me on technique.

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