The useful numbers for cell culture split into two groups: the biology numbers you read off your protocol, and the hardware numbers you have to buy. We build fermentation vessels, so this page tabulates the second group — real working volumes, materials, sterilization routes and control loops for glass and stainless lab tanks.
Which numbers actually matter in cell culture?
Ask ten labs for their useful numbers and you get ten different lists, because two different kinds of number get mixed together in the same table.
The first kind is biological. Seeding density, doubling time, viability threshold, confluence at harvest, medium exchange interval. These belong to your cell line and your protocol. They are not properties of any equipment we sell, and we are not going to reprint someone else’s version of them with our logo on top. If a number describes your cells, it comes from your cell bank record or the labware supplier’s own datasheet — not from a tank builder.
The second kind is a hardware number, and this is the group that decides what you can actually run. Working volume. Vessel material in contact with the culture. How the liquid gets stirred. How the vessel gets sterile and stays sterile. Which process variables the controller can hold: temperature, speed, pH, DO, foam, feeding, and — once you move up to steel — air flow and tank pressure.
Here is the practical difference. A biological number tells you what the culture wants. A hardware number tells you whether you can give it that. When a 5 L culture stalls, the answer is almost never in the seeding density table. It is in whether the vessel can mix and oxygenate 5 L without shearing the cells or foaming the headspace into the exhaust filter.
Why do the published reference tables stop at the flask?
Search this topic and you land on the same shape of document every time: a PDF of flask surface areas, plate well volumes, and how much medium each one takes. Useful — genuinely — for the bench. Then it ends. The tables run out exactly at the point where the interesting engineering starts, which is the moment your culture no longer fits in something you can carry to the incubator.
We think that gap exists because labware vendors publish labware numbers and vessel builders publish vessel numbers, and nobody puts them in the same view. So a process development scientist with a working protocol at flask scale has no table telling them which vessel tier the next step lands in.
That is what the rest of this page is. Below are our real published vessel specifications, laid out as reference tables in the same spirit as the flask ones you already use, so the question “what vessel matches this working volume” gets answered without a sales call.
Glass vessel reference table: 1L to 10L
This is the tier that sits directly above flask work. Everything in this table is from our Glass Fermentation Tank specification, not a range we rounded for the article.
| Total volume | 1L, 2L, 3L, 5L, 7L, 10L and multi-vessel configurations |
|---|---|
| Material | 316L stainless steel + borosilicate glass |
| Stirring | Magnetic-drive mechanical stirring; top or bottom pin-free magnetic coupling options |
| Sterilization | Off-site autoclave sterilization |
| Basic controls | Temperature, speed, pH, DO, foam control and feeding |
Three things in that table are worth reading twice. The vessel body is borosilicate glass, which means you can see the culture — foam height, colour, whether the impeller is actually moving liquid or just spinning in a cavern. At development scale that visibility is worth more than most people expect.
Second, the stirring is magnetic-drive, with pin-free magnetic coupling available top or bottom. No mechanical seal through the head plate means no seal to leak and no seal to sterilize around. For shear-sensitive animal cell work, that coupling choice is a real decision, not a catalogue detail.
Third, sterilization is off-site autoclave. The vessel goes to the autoclave; steam does not come to the vessel. That single line dictates your workflow — you need an autoclave that physically fits the vessel, and you need hands to move it. Which is fine at 1L and gets old somewhere on the way to 10L. If you want the whole 1L to 10L tier with the pin-free magnetic coupling option, the glass fermentation tank specifications and multi-vessel configurations are on the product page.
Stainless vessel reference table: 10L to 500L
The next tier up is where reference tables stop existing entirely, so here is ours.
| Total volume | 10L, 15L, 20L, 30L, 50L, 75L, 100L, 150L, 200L, 300L and 500L |
|---|---|
| Material | 316L / 304 stainless steel |
| Stirring | Top mechanical stirring or magnetic-drive mechanical stirring |
| Sterilization | In-situ steam sterilization |
| Basic controls | Temperature, speed, pH, DO, foam control, feeding, air flow and tank pressure |
Compare the two control lists and you find the most useful number on this page, which is not a number at all — it is the count of loops. Glass gives you temperature, speed, pH, DO, foam control and feeding. Steel gives you those plus air flow and tank pressure.
Air flow and tank pressure appear at this tier because they have to. Once the vessel is sealed and steamed in place, gas has to be metered in deliberately and the headspace has to sit at a controlled pressure to keep the sterile boundary sterile. At 1L in glass you can be relaxed about both. At 200L you cannot. That is why our laboratory bio fermentation tank carries air flow and tank pressure control across the 10L to 500L range while the glass tier does not.
The volume list also deserves a read. It is not a smooth curve — the steps are 10, 15, 20, 30, then 50, 75, 100, then 150, 200, 300, 500. The gaps widen as you go up, which tells you something honest about scale-up: near the bottom you can tune your vessel to your batch, and near the top you fit your batch to the vessel.
Total volume or working volume: which number do you plan around?
Every number in both tables above is a total volume. Your protocol runs on working volume. These are not the same, and confusing them is the single most common sizing error we see.
Total volume is the geometric capacity of the vessel. Working volume is how much culture you can actually put in it and still run a process. The difference is headspace — room for foam, room for gas disengagement, room for the impeller to do its job without throwing liquid at the exhaust filter, room for feed and base addition over the run.
How much headspace? That depends on your culture, and we are not going to hand you a universal ratio, because there isn’t one. A dense aerobic microbial culture that foams hard needs far more headspace than a slow, gently sparged mammalian batch. Fed-batch needs room for everything you plan to add. Your antifoam strategy changes the answer again.
So the rule we give customers is directional rather than numerical: start from your maximum working volume at end of run — including every feed, base and antifoam addition — then step up the total volume list until you have comfortable headspace above it. If your batch is 20L at harvest, you are not shopping for a 20L tank. If your batch never exceeds 20L, skip the 50L; the extra volume costs you mixing performance at low fill, not just money.
Which numbers change when you leave the shake flask?
Three categories of number appear that had no equivalent at flask scale.
Sterilization becomes a route, not a step. In the glass tier it is off-site autoclave sterilization. In the stainless tier it is in-situ steam sterilization. These are different facilities requirements, different SOPs, different amounts of labour per run. Nobody puts this in a cell culture reference table, and it changes your week more than any seeding density does.
Materials become a specification you have to state. Glass vessels are 316L stainless steel plus borosilicate glass. Steel vessels are 316L or 304 stainless steel. That 316L-or-304 choice is yours to make against your medium and cleaning chemistry, and it is the kind of thing quality auditors ask about later, so decide it deliberately.
Agitation stops being an orbital speed. A shaker has one number. A stirred vessel has an impeller type, a coupling method, and a speed set point that interacts with your oxygen transfer and your shear tolerance at the same time. The glass tier offers magnetic-drive with top or bottom pin-free coupling; the steel tier offers top mechanical or magnetic-drive. Which one you want depends on whether you are more afraid of shear or of seal integrity — that trade-off is worked through in our explanation of what a bioreactor fermenter does and how the vessel holds each control loop.
How do you match a culture volume to a vessel?
Put the two tables side by side and the map is straightforward.
Culture at a few hundred millilitres to a couple of litres, and you want eyes on it? Glass, 1L to 5L. You get visibility, magnetic-drive stirring, and the full temperature, speed, pH, DO, foam control and feeding set. You accept carrying it to an autoclave.
Running several conditions in parallel for screening? Glass again, but multi-vessel. Six small vessels running different set points beat one large vessel running one condition, every time, when the question is which condition wins.
Culture at 10L and climbing, or you have stopped wanting to lift the vessel? Stainless, and cross into in-situ steam sterilization. At 10L you have a genuine choice — that volume exists in both tables — and it is the only overlap point, so it is worth thinking about rather than defaulting.
Feeding it a defined gas rate, holding pressure, running for days? Stainless, because air flow and tank pressure control only exist at that tier. Above roughly the 50L mark you are also into facilities questions — steam supply, floor space, utilities — which we cover in our fermentation tank procurement guide covering working volume, agitation and sterilization requirements. The full ladder from 1L glass through 500L stainless sits in the fermentation tank category, where the vessel families are listed side by side.
Which numbers should you pin down before you specify?
When a customer sends us an enquiry, these are the numbers that let us answer it properly. Get them written down and any vessel builder — us or otherwise — can respond with something real instead of a brochure.
- Working volume at end of run. Not nominal batch size. The maximum liquid in the vessel after every addition.
- Agitation requirement. Impeller configuration and whether your cells tolerate a mechanical seal or need magnetic coupling.
- Temperature-control support. What set point you hold, how tightly, and what utilities you have to hold it with.
- Sterilization needs. Off-site autoclave or in-situ steam. This decides the vessel tier as much as volume does.
- Sensor requirements. pH and DO are standard across both tiers. Anything beyond that needs ports specified before the head plate is made.
- Downstream equipment. What receives the broth. It sets the discharge arrangement, and it is the item most often remembered too late.
Those six are the actual selection basis for a fermentation vessel — vessel volume, agitation, temperature support and process-control requirements. If you want them as a form rather than a list, the selection guide walks the same six points in order.
Frequently asked questions
What working volume can I run in a glass fermentation tank?
Our glass vessels are built in 1L, 2L, 3L, 5L, 7L and 10L total volumes, plus multi-vessel configurations. Your working volume sits below the total volume by whatever headspace your culture’s foaming and gas disengagement need, so plan the working volume first and pick the total volume above it.
At what volume should I move from glass to stainless steel?
10L is where the two ranges overlap, and it is the natural decision point. Below it, glass gives visibility and off-site autoclave sterilization. Above it, our stainless range continues through 15L, 20L, 30L, 50L, 75L, 100L, 150L, 200L, 300L and 500L with in-situ steam sterilization. If handling the vessel or holding gas flow is becoming the constraint, move earlier rather than later.
Which process variables can a lab fermentation vessel control?
Both tiers control temperature, speed, pH, DO, foam and feeding. The stainless laboratory bio vessels add air flow and tank pressure, which is what lets you run a sealed, steamed-in-place vessel with a defined gas supply for extended cultures.
Is 316L or 304 stainless steel the right choice for my culture?
Both are available on our stainless vessels, and our glass vessels use 316L for the metal parts. The decision belongs to your medium chemistry, chloride exposure and cleaning regime rather than to a general rule. Tell us what the vessel will see and we will specify against it instead of defaulting.
Why do published cell culture reference tables not list vessel volumes?
Because they are labware documents. They cover flasks, plates and dishes, which is where most protocols start and where most protocols stay. Once a culture outgrows that hardware you are in equipment territory, and the numbers you need — total volume, material, stirring, sterilization route, control loops — come from vessel specifications like the two tables above.
Where to start
If your culture is under 10L and you are still optimising conditions, start with glass and take the visibility. Add multi-vessel if you are comparing conditions rather than making product. If you are at or past 10L, or you need controlled air flow and tank pressure, the stainless laboratory range from 10L to 500L is the tier that carries those loops.
Bring us your working volume at end of run, your sterilization route, and what the broth goes into next. Those three settle most of the specification. If you would rather check the common questions first, our FAQ covers the recurring ones on vessel sizing and configuration.