Partial mash?

[3dB Brewing]

How do all these LODO techniques translate to partial mash brewing?

My current hot side procedure is (for a 5gal batch):
Mash 3lb grain in 1gal H2O for 1 hour.
The grain mix is all specialty grains in the recipe + enough base grain to make up 3lb; convert remaining base grain to DME
Strike at 163F, it settles to around 152-154, then mash out at 163
(I heat the mash water in a spaghetti pot then drop the grains in a BIAB into the pot and gently stir to prevent clumps, cover & insulate)
Meanwhile, heat 2qts sparge H2O and about 2gal in kettle
At mash out, I lift the bag & let drain; and put it in a colander over the brew kettle
Slowly pour wort over grains to filter (I guess that counts as a 1-time recirculation -- so, just a "circulation"?)
Pour sparge water at 170F over grain bed. Let it drain, squeeze the bag, & remove
Add H2O to kettle to get ~3.5 gal, add ~1/3 of my DME, and start hopping per recipe at boil
Gentle boil 1hr
Add remaining DME, optional cane sugar, and Whirlfloc/PVPP at 10min.
Immersion chill (yeah, it's copper. I know; I've read).
Whirlpool & let settle
Rack to plastic fermentation bucket
Add H2O to make 5gal
Pitch (typically Wyeast with the baby starter per its packaging; a 1-day yeast starter for a high gravity batch, or if I'm using White Labs)
Clariferm if it's a light ale
Aerate with O2.

This is manageable in the kitchen, without spending a fortune on gear, it takes about 4hrs, and it produces great beer.
But we can always make the beer better, right?

The first thing I changed already is a bladder instead of an airlock, to capture CO2 for protection during cold crashing, but that's for the cold side. I'm concentrating on the hot side.

So reading these forums, I learned of Yeast Oxygen Scavenging and the Trifecta. Both seem simple enough, and it sounds like the Na-meta will mitigate the use of a copper chiller. So I would need to treat all of the mash, sparge, and kettle make-up H2O.

Does it make any sense to treat the fermentation make-up H2O? I mean, I pour it in for all of 15sec. before pitching yeast, then I'm pumping in pure O2.

The other thing that stands out is that dripping the wort and sparge H2O through the grains into the brew kettle is a splashy process, so probably picking up O2?
Without a major equipment overhaul (at this stage anyway), is there a better way to get the wort into the kettle? I suppose I could just mash in the kettle and remove the grain bag, but then how do I sparge the grain? I've read that step is necessary to extract all the sugars from the grain bed. That would also omit the step of "filtering" the wort through the grain, so would leave more particulates in the boil. I'm not sure that's a bad thing, if they drop out with the cold break.

Anyway, I'd welcome any suggestions for minimizing oxidation within the general parameters of what I'm doing. It works well for me, and at this point I'm not interested in going all-grain.

 

[Brooothru]

The questions you've asking show that you are on the right track. Partial mash doesn't exclude low-oxygen techniques, but does present a few challenges. The thing to keep in mind is that oxydation is a cumulative process rather than a zero-sum, all or nothing game. Every step can bring improvement, so if you leave one process out you won't "ruin" a LoDO batch, but it won't fully achieve the improvement that is possible. What you need are some workarounds and adaptations that are achievable with what you already have, and then go from there.

First off, the yeast oxygen scavenging (YOS) method is so easy and so thorough that it should be a no-brainer to do it every time. You can treat the full volume of strike water and sparge water (more about sparging later) at the same time in your boil vessel. I like to do mine the night before I brew so I don't have to wait for an hour or so in the morning while it does its thing. The yeast will continue consuming the dissolved O2 for up to a week or until they are denatured during the boil. The next easy and yet important step is to treat the water with NaMeta or a 'Trifecta' blend before you separate out the strike water from the sparge water. That will provide an ongoing process of sequestration and protection from new O2 pickup after the deoxygenated YOS water exceeds 140F and the yeast are denatured.

The partial mash steeping of specialty grains you are doing is like a mini brew-in-a-bag. The water gets heated, the grains are dunked in, after a period of time they get pulled out and the "wort" gets boiled. The only difference here is that your "wort" lacks the sugars that would otherwise come from the additional base grains that an all-grain or full BIAB would provide. You make up for that lack of sugar by adding DME/LME. Viola! Instant beer wort ready for fermentation.

What if you slowly raised the bag out of the partial mash spaghetti pot with an overhead pulley system letting it drain back into the mash pot while keeping it partially submerged, raising it a notch at a time while the bag drained and the pot filled? This would greatly reduce splashing. After the bag is mostly drained and the pot has partially filled with the "mini-mash" strike water, take your fermenting bucket and fill it with your preheated sparge water. Slowly lower the grain bag with the specialty grains and partial base malt grains into the sparge water. Gently stir the submerged grains, just like you did at mash in, to rinse and capture any residual sugars from the grain. Then repeat the slow lifting of the bagged grains to allow the "sparge" water to drain with minimal splashing into the fermenting bucket. Now you've got your partial mash wort in the boil vessel and your sparge water in the fermenter. Combine the two in your boil pot and proceed as normal. Avoid splashing as much as possible, or use a siphon to transfer the sparge water into the boil pot. Don't forget to rinse and sanitize your fermenting bucket before using it to ferment.

Sparging is a big potential problem area because of the dripping and splashing. On the one hand you want to avoid splashing because that's a major area of oxygen pickup. You went to the trouble of YOS to get rid of O2, now you want to put it right back in? No way. I try to not sparge and just over-build my grain bill to compensate. That's hard to do in the partial mash like you do. You need the sugars and the enzymes from the grains to convert the partial mash. You need to recover as much of the converted sugars from the grain bed. As long as you take steps to minimize the splashing and treat the mash and sparge water with NaMeta/Trifecta you will be minimizing potential damaging O2 pickup.

That's about it for the hot side, but as a last step I add a second, slightly smaller, dosing of NaMeta/Trifecta late in the boil. This helps to chelate any oxides from copper chillers and extend protections from splashing and O2 pickup when transferring from the boil pot into the fermenter. I also stir the chilled wort to whirlpool as many solids out before transferring to the fermenter. After about 5 minutes of gentle stirring (don't splash) and 20 to 30 minutes of settling (cover ON), the wort is very clear and most of the trub has settled out, which I have to attribute to the Trifecta possibly working with the Whirlfloc to precipitate solids more efficiently. Either way it's quite noticeable and desirable.

One brief word about cold side: don't worry about damaging the wort by oxygenating it for the benefit of the yeast. They want it and need it for propagation and cell growth. As long as you pitch the yeast first, then oxygenate, an active yeast colony will consume the O2 in short order. Then they will take over the task of removing any future O2 incursion as long as you do your part and keep the lid shut on the fermenter.

BIG Caveat:

If you're using dry yeast, you don't need to oxygenate at all. Unlike liquid yeast, the dried yeast cells themselves contain sufficient glycogen reserves to fuel their early growth stage without injecting dissolved O2 into the wort.

Do what you can, what you are willing to do, what makes sense to you and what your set up will allow you to do within your constraints. You can achieve a lot by spending a little, and even more if you want to make major investments in gear. But you don't have to go all in to have a positive effect. Just remember, each step is helping in its own way to improve the quality and stability of your beer.

Prost!

 

[VikeMan]

If you're using dry yeast, you don't need to oxygenate at all. Unlike liquid yeast, the dried yeast cells themselves contain sufficient glycogen reserves to fuel their early growth stage without injecting dissolved O2 into the wort.

The reason is actually sterol reserves. Yeast normally O2 to make sterols for cell wall building and budding. But dry yeast is already full of sterol reserves.

 

[3dB Brewing]

Ah, that makes sense! So sparging becomes essentially a secondary mash, at a higher temp for a shorter time (which I guess it kinda is now, with the pour-through).

Thanks for the idea; I'll give it a try next batch!

Do I guess correctly that H2O added to the fermenter just prior to yeast pitch need not be deoxygenated? I suppose it couldn't hurt; just trying to keep the workload down if there's no benefit.

 

[Brooothru]

The reason is actually sterol reserves. Yeast normally O2 to make sterols for cell wall building and budding. But dry yeast is already full of sterol reserves.

Correct. I'd blame my mistake on the antihistamines I'm taking for allergies, but that would be a lame attempt at deflecting my occasional show of ignorance.

 

[Brooothru]

Ah, that makes sense! So sparging becomes essentially a secondary mash, at a higher temp for a shorter time (which I guess it kinda is now, with the pour-through).

Thanks for the idea; I'll give it a try next batch!

Do I guess correctly that H2O added to the fermenter just prior to yeast pitch need not be deoxygenated? I suppose it couldn't hurt; just trying to keep the workload down if there's no benefit.

Adding strictly deoxygenated water (like pre-boiling) to the wort would I think have a neutral effect especially if the yeast have already been pitched. However, there will always be 'some' effect on the chemical composition of the wort when either NaMeta or Trifecta blend is added. Whether it is significant or discernible is doubtful since the amounts are relatively small, but it's above my pay grade to say definitively one way or the other. I see a slight risk for marginal benefit. When in doubt, leave it out.

 

[effeffe]

While it's true that dry yeast doesn't need oxygen, if you're using sulfites as antioxidants you still have to oxygenate the wort to expend them before pitching.

 

[Brooothru]

I've heard that this is true and it seems logical. But as @VikeMan pointed out yeast normally use O2 to produce sterols for cell wall construction, however the dried yeast already have sufficient sterols for budding and daughter cell production.

OTOH, with liquid yeast supplemental O2 is necessary for the early growth phase. The effects of deoxidation of the wort would have to be countered adequately (but not overdone) to accommodate this deficiency for the yeast without putting oxidative stress on the wort. The German LOB brewers advocate pitching liquid yeast prior to oxygenation to reduce the exposure time of the wort to oxygen before it is consumed by the yeast.

How much O2 is enough and how much is too much is the real question, and that's largely dependent on the heath and phase, as well as size, of the pitch. A weeks old 500 ml pitch will certainly require a greater amount of O2 than a 1L pitch at high krausen, which may require little if any O2 supplement, to achieve the same fermentation results.

 

[effeffe]

I've heard that this is true and it seems logical. But as @VikeMan pointed out yeast normally use O2 to produce sterols for cell wall construction, however the dried yeast already have sufficient sterols for budding and daughter cell production.

OTOH, with liquid yeast supplemental O2 is necessary for the early growth phase. The effects of deoxidation of the wort would have to be countered adequately (but not overdone) to accommodate this deficiency for the yeast without putting oxidative stress on the wort. The German LOB brewers advocate pitching liquid yeast prior to oxygenation to reduce the exposure time of the wort to oxygen before it is consumed by the yeast.

How much O2 is enough and how much is too much is the real question, and that's largely dependent on the heath and phase, as well as size, of the pitch. A weeks old 500 ml pitch will certainly require a greater amount of O2 than a 1L pitch at high krausen, which may require little if any O2 supplement, to achieve the same fermentation results.

If you were replying to me, I'm not sure I follow. I was just saying that, when using sulfites as antioxidants, some oxygenation is needed before pitching regardless of what kind of yeast you're using, because you don't want yeast and sulfites together, so you oxygenate to expend those sulfites before pitching yeast.
If you're using liquid yeast, you can first oxygenate only as much as needed to expend your sulfites, then pitch, then oxygenate to the amount of oxygen your yeast needs.

If it wasn't for me, sorry.

 

[Brooothru]

If you were replying to me, I'm not sure I follow. I was just saying that, when using sulfites as antioxidants, some oxygenation is needed before pitching regardless of what kind of yeast you're using, because you don't want yeast and sulfites together, so you oxygenate to expend those sulfites before pitching yeast.
If you're using liquid yeast, you can first oxygenate only as much as needed to expend your sulfites, then pitch, then oxygenate to the amount of oxygen your yeast needs.

If it wasn't for me, sorry.

O.K., I believe I see the distinction now. You're saying that there's a negative interaction between the yeast and the antioxidants, so injecting O2 into the wort reduces/eliminates the level of sulfite in the wort. Once that is accomplished the yeast can be pitched and additional O2 injected to aid in early stage yeast propagation. This would then apply to both liquid and dry yeast pitches.

What I don't understand is the nature of the negative interaction of sulfites and yeast, and whether that bad effect presents a greater or lesser threat than oxidation. I'm not doubting there is one. I'm just not familiar with what it is.

 

[effeffe]

O.K., I believe I see the distinction now. You're saying that there's a negative interaction between the yeast and the antioxidants, so injecting O2 into the wort reduces/eliminates the level of sulfite in the wort. Once that is accomplished the yeast can be pitched and additional O2 injected to aid in early stage yeast propagation. This would then apply to both liquid and dry yeast pitches.

What I don't understand is the nature of the negative interaction of sulfites and yeast, and whether that bad effect presents a greater or lesser threat than oxidation. I'm not doubting there is one. I'm just not familiar with what it is.

Sulfites increase the production of hydrogen sulfide by yeast, and since it can cause nasty off-flavors, it's considered worse than a touch of oxidation. The working hypothesis is that oxidation here isn't critical for two reasons: yeast will be pitched soon and will consume oxygen, and the low temperature at this step of the brewing process slows down oxidation reactions by a lot.

 

[Brooothru]

Sulfites increase the production of hydrogen sulfide by yeast, and since it can cause nasty off-flavors, it's considered worse than a touch of oxidation. The working hypothesis is that oxidation here isn't critical for two reasons: yeast will be pitched soon and will consume oxygen, and the low temperature at this step of the brewing process slows down oxidation reactions by a lot.

Good explanation. I haven't noticed H2S in my beers but I can appreciate the concern about avoiding it. It seems as though the escaping CO2 would carry off gaseous H2S early in the fermentation, so is the thinking that some is retained rather than passing out through the airlock? Also, how much 'pre-oxing' of the wort would be required to reduce the effects of ~1 gram of NaMeta?

My whole focus has been on eliminating as much D.O. in the wort as possible without considering the formation of something potentially as bad. That said, the negative consequences of oxidation are permanent. If the downside of H2S production is transient, as it often is in wine, then I can live with that.

 

[effeffe]

Good explanation. I haven't noticed H2S in my beers but I can appreciate the concern about avoiding it. It seems as though the escaping CO2 would carry off gaseous H2S early in the fermentation, so is the thinking that some is retained rather than passing out through the airlock? Also, how much 'pre-oxing' of the wort would be required to reduce the effects of ~1 gram of NaMeta?

My whole focus has been on eliminating as much D.O. in the wort as possible without considering the formation of something potentially as bad. That said, the negative consequences of oxidation are permanent. If the downside of H2S production is transient, as it often is in wine, then I can live with that.

Some hydrogen sulfide is surely retained, but I don't know how much. Also, the low oxygen brewing process includes spunding, which I guess retains more volatile compounds, but I'm speculating.

I don't remember the numbers off the top of my head, but I'm sure they're somewhere on The **************** website, though pretty much everything is happening on the forums there and not on the blog. You can also find relevant information on these topics here.

Edit: damn censorship. Oh well, you know what I'm talking about.

 

[3dB Brewing]

OK, I tried it, and the result was... bizarre.
I adopted @Brooothru 's suggestions for HSA mitigation in my partial mash routine. I realize one error was changing numerous things at once; now I can't figure out which went weird.

What I did (* means this was new):
Belgian Dubbel recipe (one of my favorites; brewed it many times)
YOS treated 5 gal the night before *
Trifecta into the 5 gal *
Normal mash -- 3 lbs grain in 1 gal H2O @ 163F; settles to 152-54 for one hour; mash out at 168.
Heated 2 gal H2O to 170 in brew kettle and sparged (more like washed) the grains in that *
From there it was a normal boil (hops, DME, cane sugar per recipe)
I added Brewtan at the end * (prior to WF+PVVC)
Chill & whirlpool for several hours
Racked wort off of hot break trub *
into a keg *
(Not really "trub" like I've ever seen -- more like the bottom several inches of the kettle had a thick dark ooze mixed with the wort. This was all hot break; I boiled the hops in a strainer. I will say this was the cleanest wort I've ever started fermentation with.)
Added H2O to make 5 gal
OG = 1.060
My LHBS was out of Wyeast 3787 so I used White Labs 530. I didn't make a starter, but I pitched two vials.
Aerated with O2
for like 3 minutes due to sulfides *

I've never waited more than 24 hours to see airlock activity with this recipe. I ran a tube out of the gas post into a jar of StarSan. Next day -- nothing. 3 days, 4 days -- nothing.

7 days later -- nothing. I opened it up and took a gravity reading. 1.060. I figured the yeast was bad, so I tried a Hail Mary and pitched 2 vials of Wyeast 3787. No O2 aeration because now I'm thinking I killed the wort with O2 the first time, if the yeast wasn't taking it up.

Next day -- nothing. 3 days, 4 days -- nothing.

At this point, I said to myself "F this. I'm out of beer." So I bought the whole grain bill over and some more yeast, and planed my conventional brew day, which probably infuses O2 but at least it makes beer! This time I got one vial of WLP530 and made a starter 24 hrs. ahead. Made a 1.062 wort.

While I'm heating up mash and sparge water, I went to dump the first batch and clean out the keg... and THE DARN THING IS BUBBLING LIKE CRAZY. This is 14 days after the first pitch; and 7 days after the second pitch!

I brewed the second batch my old way (see top of this thread), no Brewtan (WF only), and in 6 HOURS I had bubbling. By 24 hours it had gone volcanic and wort was being ejected into my StarSan. This went on for 2 days. It must have blown out a good 2 pints of wort. It was done by day 3. In contrast, the first batch is now on day 4 and still bubbling (slower, but it's still going). So not only was there a dramatic difference in the onset of fermentation, they are also proceeding at very different rates.

Since they both started fermenting on the same day (the first batch just had to sit there and think it over for 2 weeks), I'm going to treat them the same from here on out (closed xfer, carb, etc.) and compare the finished products.

But darn if I can figure what happened to that first batch.

 

[Brooothru]

OK, I tried it, and the result was... bizarre.
I adopted @Brooothru 's suggestions for HSA mitigation in my partial mash routine. I realize one error was changing numerous things at once; now I can't figure out which went weird.

What I did (* means this was new):
Belgian Dubbel recipe (one of my favorites; brewed it many times)
YOS treated 5 gal the night before *
Trifecta into the 5 gal *
Normal mash -- 3 lbs grain in 1 gal H2O @ 163F; settles to 152-54 for one hour; mash out at 168.
Heated 2 gal H2O to 170 in brew kettle and sparged (more like washed) the grains in that *
From there it was a normal boil (hops, DME, cane sugar per recipe)
I added Brewtan at the end * (prior to WF+PVVC)
Chill & whirlpool for several hours
Racked wort off of hot break trub *
into a keg *
(Not really "trub" like I've ever seen -- more like the bottom several inches of the kettle had a thick dark ooze mixed with the wort. This was all hot break; I boiled the hops in a strainer. I will say this was the cleanest wort I've ever started fermentation with.)
Added H2O to make 5 gal
OG = 1.060
My LHBS was out of Wyeast 3787 so I used White Labs 530. I didn't make a starter, but I pitched two vials.
Aerated with O2
for like 3 minutes due to sulfides *

I've never waited more than 24 hours to see airlock activity with this recipe. I ran a tube out of the gas post into a jar of StarSan. Next day -- nothing. 3 days, 4 days -- nothing.

7 days later -- nothing. I opened it up and took a gravity reading. 1.060. I figured the yeast was bad, so I tried a Hail Mary and pitched 2 vials of Wyeast 3787. No O2 aeration because now I'm thinking I killed the wort with O2 the first time, if the yeast wasn't taking it up.

Next day -- nothing. 3 days, 4 days -- nothing.

At this point, I said to myself "F this. I'm out of beer." So I bought the whole grain bill over and some more yeast, and planed my conventional brew day, which probably infuses O2 but at least it makes beer! This time I got one vial of WLP530 and made a starter 24 hrs. ahead. Made a 1.062 wort.

While I'm heating up mash and sparge water, I went to dump the first batch and clean out the keg... and THE DARN THING IS BUBBLING LIKE CRAZY. This is 14 days after the first pitch; and 7 days after the second pitch!

I brewed the second batch my old way (see top of this thread), no Brewtan (WF only), and in 6 HOURS I had bubbling. By 24 hours it had gone volcanic and wort was being ejected into my StarSan. This went on for 2 days. It must have blown out a good 2 pints of wort. It was done by day 3. In contrast, the first batch is now on day 4 and still bubbling (slower, but it's still going). So not only was there a dramatic difference in the onset of fermentation, they are also proceeding at very different rates.

Since they both started fermenting on the same day (the first batch just had to sit there and think it over for 2 weeks), I'm going to treat them the same from here on out (closed xfer, carb, etc.) and compare the finished products.

But darn if I can figure what happened to that first batch.

The clean wort is one pretty shocking visual result of BrewTan. Did you also mix it with ascorbic acid and NaMeta? Too much Meta can result in NO dissolved oxygen, even after you oxygenate the wort AFTER pitching the yeast. It's pretty effective at elimating D.O., which the yeast need to get started. It doesn't take much. I used 1.4 grams of Trifecta (0.6 grams BrewTan, 0.4 gr. each ascorbic and NaMeta) for a 6.3 gallon fermentation. If I use much more than that, the lag phase can take a day or two. If you didn't get a start at all, it might have been too much antioxidant in the wort, an under-pitch of viable yeast, or a combination. I know the German brewers initially had issues of slow start/weak fermentations and now advocate smaller dosing of Trifecta.

 

[3dB Brewing]

Yes, all three. I used a formula I found here: 30ppm * 5gal * 0.003785 = ~0.6g for NaMeta and AA. Wyeast's website says 8g/bbl for Brewtan = ~0.2g for 5gal. That's inverse to the mix you mention above. So to scale your mix down to 5gal would be 0.47g BT and 0.32 NM and AA -- roughly twice the BT I used and half the NM/AA.

So if it was too little O2, then what saved the batch was opening it up, taking a gravity reading, and pitching new yeast, all of which exposed the wort to air? But then it still took another week to start fermentation...

 

[Brooothru]

Yes, all three. I used a formula I found here: 30ppm * 5gal * 0.003785 = ~0.6g for NaMeta and AA. Wyeast's website says 8g/bbl for Brewtan = ~0.2g for 5gal. That's inverse to the mix you mention above. So to scale your mix down to 5gal would be 0.47g BT and 0.32 NM and AA -- roughly twice the BT I used and half the NM/AA.

So if it was too little O2, then what saved the batch was opening it up, taking a gravity reading, and pitching new yeast, all of which exposed the wort to air? But then it still took another week to start fermentation...

That really is strange. I've never experienced that problem you had with yeast being a total non-starter. I've been using yeast oxygen scavenging and Trifecta dosing of both the mash and late boil in all my brew sessions for at least the past 15 months (20 brews +/-). No issues like you described, except one or two that took 30~40 hours to reach high Krausen instead of my usual 'overnight' startup.